Greatbear were recently approached by the Courtyard Music Group to help them complete the 100% analogue re-issue of their 1974 acid-folk album Just Our Way of Saying Hello.
Among Britfolk enthusiasts, news of the Courtyard Music Group’s plans to re-issue their album has been greeted with excitement and anticipation.
Just Our Way of Saying Hello was created when ‘an idealistic young teacher cut a lo-fi folk-rock record with a bunch of teenagers in the Utopian rural setting of Kilquhanity School in the Scottish borders.’
100 copies of the album were made in a private pressing, originally intended for family and friends.
Yet this was not the end of the story, as the record went on to become ‘one of the most obscure albums in Britfolk history is now an ultra-rare collector’s item, with copies trading online for over £1000.’
After a hugely successful pledge music campaign, the band are pushing ahead with their re-issue project that will produce a limited pressing of the mono vinyl, a remastered audio CD with outtakes and a 48 page booklet with interviews, photos and drawings. These will all be available in the summer of 2015.
Great Bear’s role in the project was twofold: first to restore the physical condition of tapes in order to achieve the best quality transfer. Second to produce analogue copies of the original master tapes. These second generation masters, originally recorded at a speed of 7½ inches per second, were transferred at the speed of 15 ips in our studio.
These copies were then sent to Timmion Records in Finland to complete the final, analogue only cutting of the re-issue. Even amid the much discussed ‘vinyl revival‘ there are currently no UK-based studios that do pure analogue reproductions. The risk of losing precious cargo in transit to Finland was too great, hence our involvement at the copying stage.
The original master tapes
Analogue only
Why was it so important to members of the Courtyard Music Group to have an analogue only release? Digital techniques began creeping into the production of audio recordings from the late 1970s onwards, to the situation today where most studios and music makers work in an exclusively digital environment.
Can anyone really tell the difference between an analogue and digital recording, or even a recording that has been subject to a tiny bit of ‘digital interference’?
Frank Swales, member of the Courtyard Music Group, explains how remaining true to analogue was primarily a preference for authenticity.
‘I think in this case it’s really about the JOURNEY that this particular product has had, and the measures taken to keep it as close to the original product as possible. So, I’m not sure anyone can, in a listening context, perceive any real difference between digital and analogue, given that all of us humans are pretty much restricted to the frequency range of 20Hz to 20kHz, if we’re lucky!’
While Richard Jones, also a member of Courtyard Music Group, revealed: ‘Our 1974 recording was made using a selection of microphones, some ribbon, a valve powered four channel mixer and an ancient Ferrograph tape recorder. I cannot claim these decisions about the analogue reissue are soundly based on principles of Acoustics/physics. They are decisions to produce an authentic product. That is, attempting to eliminate the introduction of “colours” into the sound which were not there in 1974.’
The ability to create exact copies is perilously difficult to achieve in an analogue context. Even in the most controlled circumstances analogue transfers are always different from their ‘original.’ The tape might distort at high frequencies for example, or subtle noise will be created as the tape moves through the transport mechanism.
Yet the desire for analogue authenticity is not the same as wanting a replica. It is about preserving historically specific sound production process whose audible traces are becoming far less discernible.
After all, if authenticity was correlated with exact replication, the Courtyard Music Group would not have asked us to make the copies at a higher recording speed than the originals. Yet, Frank explains, ‘the difference in sound quality – the tracks especially having been recorded onto tape travelling at 15ips – will likely be negligible, but it must be said that this was a decision not lightly taken.’
By preserving the historical authenticity of analogue reproduction, the Courtyard Music Group re-issue project converges with the archival concern to maintain the provenance of archival objects. This refers to when the ‘significance of archival materials is heavily dependent on the context of their creation, and that the arrangement and description of these materials should be directly related to their original purpose and function.’
For a range of audiovisual objects made in the late 20th and early 21st centuries, such fidelity to the recording and its context will be increasingly difficult to realise.
As appropriate playback machines and recordable media become increasingly difficult to source, an acceptance of hybridity over purity may well be necessary if a whole range of recordings are to be heard at all.
We are not yet at that stage, thankfully, and Greatbear are delighted to have played a part in helping spread the analogue purity just that little bit further.
***Thanks to Courtyard Music Group members for answering questions for this article.***
In one of our most popular posts, we discussed how Videokunstarkivet has created a state of the video art archive using open source software to preserve, manage and disseminate Norway’s video art histories for contemporary audiences and beyond.
In Lives and Videotapes, the beautiful collection of artist’s oral histories collected as part of the Videokunstarkivet project, the history of Norwegian video art is framed as ‘inconsistent’.
This is because, Mike Sperlinger eloquently writes, ‘in such a history, you have navigate by the gaps and contradictions and make these silences themselves eloquent. Videotapes themselves are like lives in that regard, the product of gaps and dropout—the shedding not only of their material substance, but of the cultural categories which originally sustained them’ (8).
The question of shedding, and how best to preserve the integrity of audiovisual archive object is of course a vexed one that we have discussed at length on this blog.
It is certainly an issue for the last collection of tapes that we received from Videokunstarkivet—a number of very mouldyU-matic tapes.
According to the Preservation Self-Assessment Program website, ‘due to media and hardware obsolescence’ U-matic ‘should be considered at high preservation risk.’
At Greatbear we have stockpiled quite a few different U-matic machines which reacted differently to the Videokunstarkivet tapes.
As you can see from the photo, they were in a pretty bad way.
Note the white, dusty-flaky quality of the mould in the images. This is what tape mould looks like after it has been rendered inactive, or ‘driven into dormancy.’ If mould is active it will be wet, smudging if it is touched. In this state it poses the greatest risk of infection, and items need to be immediately isolated from other items in the collection.
Once the mould has become dormant it is fairly easy to get the mould off the tape using brushes, vacuums with HEPA filters and cleaning solutions. We also used a machine specifically for the cleaning process, which was cleaned thoroughly afterwards to kill off any lingering mould.
This extract demonstrates how the VO9800 replayed the whole tape yet the quality wasn’t perfect. The tell-tale signs of mould infestation are present in the transferred signal.
Visual imperfections, which begin as tracking lines and escalate into a fuzzy black out of the image, is evidence of how mould has extended across the surface of the tape, preventing a clear reading of the recorded information.
Despite this range of problems, the V09800 replayed the whole tape in one go with no head clogs.
In its day, the BVU950 was a much higher specced U-matic machine than the VO9800. As the video extract demonstrates, it replayed some of the tape without the artefacts produced by the V09800 transfer, probably due to the deeper head tip penetration.
Yet this deeper head penetration also meant extreme tape head clogs on the sections that were affected badly by mould—even after extensive cleaning.
This, in turn, took a significant amount of time to remove the shedded material from the machine before the transfer could continue.
Mould problems
The play back of the tapes certainly underscores how deeply damaging damp conditions are for magnetic tape collections, particularly when they lead to endemic mould growth.
As Mike Sperlinger writes above, the shedding and drop outs are important artefacts in themselves. They mark the life-history of magnetic tapes, objects which so-often exist at the apex of neglect and recovery.
The question we may ask is: which transfer is better and more authentic? Yet this question is maddeningly difficult to answer in an analogue world defined by the continuous variation of the played back signal. And this variation is certainly amplified within the context of archival transfers when damage to tape has become accelerated, if not beyond repair.
At Greatbear we are in the good position of having a number of machines which enables us to test and experiment different approaches.
One thing is clear: for challenging collections, such as these items from the Videokunstarkivet, there is no one-size-fits-all answer to achieve the optimal transfer.
While this is by no means a final figure (and does not include the holdings of record companies and DATheads), it does suggest there is a significant amount of audio recorded on this obsolete format which, under certain conditions, is subject to catastrophic signal loss.
The conditions we are referring to is that old foe of magnetic tape: mould.
In contrast with existing research about threats to DAT, which emphasise how the format is threatened by ‘known playback problems that are typically related to mechanical alignment’, the biggest challenges we consistently face with DATs is connected to mould.
It is certainly acknowledged that ‘environmental conditions, especially heat, dust, and humidity, may also affect cassettes.’
Nevertheless, the specific ways mould growth compromise the very possibility of successfully playing back a DAT tape have not yet been fully explored. This in turn shapes the kinds of preservation advice offered about the format.
What follows is an attempt to outline the problem of mould growth on DATs which, even in minimal form, can pretty much guarantee the loss of several seconds of recording.
Tape width issues
The first problem with DATs is that they are 4mm wide, and very thin in comparison to other forms of magnetic tape.
The size of the tape is compounded by the helical method used in the format, which records the signal as a diagonal stripe across the tape. Because tracks are written onto the tape at an angle, if the tape splits it is not a neat split that can be easily spliced together.
The only way to deal with splits is to wind the tape back on to the tape transport or use leader tape to stick the tape back together at the breaking point.
Either way, you are guaranteed to lose a section of the tape because the helical scan has imprinted the recorded signal at a sharp, diagonal angle. If a DAT tape splits, in other words, it cuts through the diagonal signal, and because it is digital rather than analogue audio, this results in irreversible signal loss.
And why does the tape split? Because of the mould!
If you play back a DAT displaying signs of dormant mould-growth it is pretty much guaranteed to split in a horrible way. The tape therefore needs to be disassembled and wound by hand. This means you can spend a lot of time restoring DATs to a playable condition.
Rewinding by hand is however not 100% fool-proof, and this really highlights the challenges of working with mouldy DAT tape.
Often mould on DATs is visible on the edge of the tape pack because the tape has been so tightly wound it doesn’t spread to the full tape surface.
In most cases with magnetic tape, mould on the edge is good news because it means it has not spread and infected the whole of the tape. Not so with DAT.
Even with tiny bits of mould on the edge of the tape there is enough to stick it to the next bit of tape as it is rewound.
When greater tension is applied in an attempt to release the mould, due to stickiness, the tape rips.
A possible and plausible explanation for DAT tape ripping is that due to the width and thinness of the tape the mould is structurally stronger than the tape itself, making it easier for the mould growth to stick together.
When tape is thicker, for example with a 1/4 ” open reel tape, it is easier to brush off the dormant mould which is why we don’t see the ripping problem with all kinds of tape.
Our experience confirms that brushing off dormant mould is not always possible with DATs which, despite best efforts, can literally peel apart because of sticky mould.
What, then, is to be done to ensure that the 3353 (and counting) DAT tapes in existence remain in a playable condition?
One tangible form of action is to check that your DATs are stored at the appropriate temperature (40–54°F [4.5–12°C]) so that no mould growth develops on the tape pack.
The other thing to do is simple: get your DAT recordings reformatted as soon as possible.
While we want to highlight the often overlooked issue of mould growth on DATs, the problems with machine obsolescence, a lack of tape head hours and mechanical alignment problems remain very real threats to successful transfer of this format.
Our aim at the Greatbear is to continue our research in the area of DAT mould growth and publish it as we learn more.
As ever, we’d love to hear about your experiences of transferring mouldy DATs, so please leave a comment below if you have a story to share.
In the last Greatbear article we quoted sage advice from the International Association of Audiovisual Archivists: ‘Optimal preservation measures are always a compromise between many, often conflicting parameters.’ [1]
While this statement is true in general for many different multi-format collections, the issue of compromise and conflicting parameters becomes especially apparent with the preservation of digitized and born-digital video. The reasons for this are complex, and we shall outline why below.
Lack of standards (or are there too many formats?)
Carl Fleischhauer writes, reflecting on the Federal Agencies Digitization Guidelines Initiative (FADGI) research exploring Digital File Formats for Videotape Reformatting (2014), ‘practices and technology for video reformatting are still emergent, and there are many schools of thought. Beyond the variation in practice, an archive’s choice may also depend on the types of video they wish to reformat.’ [2]
We have written in depth on this blog about the labour intensity of digital information management in relation to reformatting and migration processes (which are of course Greatbear’s bread and butter). We have also discussed how the lack of settled standards tends to make preservation decisions radically provisional.
In contrast, we have written about default standards that have emerged over time through common use and wide adoption, highlighting how parsimonious, non-interventionist approaches may be more practical in the long term.
The problem for those charged with preserving video (as opposed to digital audio or images) is that ‘video, however, is not only relatively more complex but also offers more opportunities for mixing and matching. The various uncompressed-video bitstream encodings, for example, may be wrapped in AVI, QuickTime, Matroska, and MXF.’ [3]
What then, is this ‘mixing and matching’ all about?
It refers to all the possible combinations of bitsteam encodings (‘codecs’) and ‘wrappers’ that are available as target formats for digital video files. Want to mix your JPEG2000 – Lossless with your MXF, or ffv1 with your AVI? Well, go ahead!
What then is the difference between a codec and wrapper?.
As the FADGI report states: ‘Wrappers are distinct from encodings and typically play a different role in a preservation context.’ [4]
The wrapper or ‘file envelope’ stores key information about the technical life or structural properties of the digital object. Such information is essential for long term preservation because it helps to identify, contextualize and outline the significant properties of the digital object.
Information stored in wrappers can include:
Content (number of video streams, length of frames),
Context (title of object, who created it, description of contents, re-formatting history),
Video rendering (Width, Height and Bit-depth, Colour Model within a given Colour Space, Pixel Aspect Ratio, Frame Rate and Compression Type, Compression Ratio and Codec),
Audio Rendering – Bit depth and Sample Rate, Bit Rate and compression codec, type of uncompressed sampling.
Codecs, on the other hand, define the parameters of the captured video signal. They are a ‘set of rules which defines how the data is encoded and packaged,’ [5] encompassing Width, Height and Bit-depth, Colour Model within a given Colour Space, Pixel Aspect Ratio and Frame Rate; the bit depth and sample rate and bit rate of the audio.
Although the wrapper is distinct from the encoded file, the encoded file cannot be read without its wrapper. The digital video file, then, comprises of wrapper and at least one codec, often two, to account for audio and images, as this illustration from AV Preserve makes clear.
Diagram taken from AV Preserve’s A Primer on Codecs for Moving Image and Sound Archives
Pick and mix complexity
Why then, are there so many possible combinations of wrappers and codecs for video files, and why has a settled standard not been agreed upon?
Fleischhauer at The Signal does an excellent job outlining the different preferences within practitioner communities, in particular relating to the adoption of ‘open’ and commercial/ proprietary formats.
Compellingly, he articulates a geopolitical divergence between these two camps, with those based in the US allegedly opting for commercial formats, and those in Europe opting for ‘open.’ This observation is all the more surprising because of the advice in FADGI’s Creating and Archiving Born Digital Video: ‘choose formats that are open and non-proprietary. Non-proprietary formats are less likely to change dramatically without user input, be pulled from the marketplace or have patent or licensing restrictions.’ [6]
One answer to the question: why so many different formats can be explained by different approaches to information management in this information-driven economy. The combination of competition and innovation results in a proliferation of open source and their proprietary doubles (or triplets, quadruples, etc) that are constantly evolving in response to market ‘demand’.
Impact of the Broadcast Industry
An important area to highlight driving change in this area is the role of the broadcast industry.
Format selections in this sector have a profound impact on the creation of digital video files that will later become digital archive objects.
In the world of video, Kummer et al explain in an article in the IASA journal, ‘a codec’s suitability for use in production often dictates the chosen archive format, especially for public broadcasting companies who, by their very nature, focus on the level of productivity of the archive.’ [7] Broadcast production companies create content that needs to be able to be retrieved, often in targeted segments, with ease and accuracy. They approach the creation of digital video objects differently to how an archivist would, who would be concerned with maintaining file integrity rather ensuring the source material’s productivity.
Furthermore, production contexts in the broadcast world have a very short life span: ‘a sustainable archiving decision will have to made again in ten years’ time, since the life cycle of a production system tends to be between 3 and 5 years, and the production formats prevalent at that time may well be different to those in use now.’ [8]
Take, for example, H.264/ AVC ‘by far the most ubiquitous video coding standard to date. It will remain so probably until 2015 when volume production and infrastructure changes enable a major shift to H.265/ HEVC […] H.264/ AVC has played a key role in enabling internet video, mobile services, OTT services, IPTV and HDTV. H.264/ AVC is a mandatory format for Blu-ray players and is used by most internet streaming sites including Vimeo, youtube and iTunes. It is also used in Adobe Flash Player and Microsoft Silverlight and it has also been adopted for HDTV cable, satellite, and terrestrial broadcasting,’ writes David Bull in his book Communicating Pictures.
HEVC, which is ‘poised to make a major impact on the video industry […] offers to the potential for up to 50% compression efficiency improvement over AVC.’ Furthermore, HEVC has a ‘specific focus on bit rate reduction for increased video resolutions and on support for parallel processing as well as loss resilience and ease if integration with appropriate transport mechanisms.’ [9]
Increased compression
The development of codecs for use in the broadcast industry deploy increasingly sophisticated compression that reduce bit rate but retain image quality. As AV Preserve explain in their codec primer paper, ‘we can think of compression as a second encoding process, taking coded information and transferring or constraining it to a different, generally more efficient code.’ [10]
The explosion of mobile, video data in the current media moment is one of the main reasons why sophisticated compression codecs are being developed. This should not pose any particular problems for the audiovisual archivist per se—if a file is ‘born’ with high degrees of compression the authenticity of the file should not ideally, be compromised in subsequent migrations.
Nevertheless, the influence of the broadcast industry tells us a lot about the types of files that will be entering the archive in the next 10-20 years. On a perceptual level, we might note an endearing irony: the rise of super HD and ultra HD goes hand in hand with increased compression applied to the captured signal. While compression cannot, necessarily, be understood as a simple ‘taking away’ of data, its increased use in ubiquitous media environments underlines how the perception of high definition is engineered in very specific ways, and this engineering does not automatically correlate with capturing more, or better quality, data.
Like error correction that we have discussed elsewhere on the blog, it is often the anticipation of malfunction that is factored into the design of digital media objects. These, in turn, create the impression of smooth, continuous playback—despite the chaos operating under the surface. The greater clarity of the visual image, the more the signal has been squeezed and manipulated so that it can be transmitted with speed and accuracy. [11]
MXF
Staying with the broadcast world, we will finish this article by focussing on the MXF wrapper that was ‘specifically designed to aid interoperability and interchange between different vendor systems, especially within the media and entertainment production communities. [MXF] allows different variations of files to be created for specific production environments and can act as a wrapper for metadata & other types of associated data including complex timecode, closed captions and multiple audio tracks.’ [12]
The Presto Centre’s latest TechWatch report (December 2014) asserts ‘it is very rare to meet a workflow provider that isn’t committed to using MXF,’ making it ‘the exchange format of choice.’ [13]
We can see such adoption in action with the Digital Production Partnership’s AS-11 standard, which came into operation October 2014 to streamline digital file-based workflows in the UK broadcast industry.
While the FADGI reports highlights the instability of archival practices for video, the Presto Centre argue that practices are ‘currently in a state of evolution rather than revolution, and that changes are arriving step-by-step rather than with new technologies.’
They also highlight the key role of the broadcast industry as future archival ‘content producers,’ and the necessity of developing technical processes that can be complimentary for both sectors: ‘we need to look towards a world where archiving is more closely coupled to the content production process, rather than being a post-process, and this is something that is not yet being considered.’ [14]
The world of archiving and reformatting digital video is undoubtedly complex. As the quote used at the beginning of the article states, any decision can only ever be a compromise that takes into account organizational capacities and available resources.
What is positive is the amount of research openly available that can empower people with the basics, or help them to delve into the technical depths of codecs and wrappers if so desired. We hope this article will give you access to many of the interesting resources available and some key issues.
As ever, if you have a video digitization project you need to discuss, contact us—we are happy to help!
References:
[1] IASA Technical Committee (2014) Handling and Storage of Audio and Video Carriers, 6.
[2] Carl Fleischhauer, ‘Comparing Formats for Video Digitization.’http://blogs.loc.gov/digitalpreservation/2014/12/comparing-formats-for-video-digitization/.
[3] Federal Agencies Digital Guidelines Initiative (FADGI), Digital File Formats for Videotape Reformatting Part 5. Narrative and Summary Tables. http://www.digitizationguidelines.gov/guidelines/FADGI_VideoReFormatCompare_pt5_20141202.pdf, 4.
[4] FADGI, Digital File Formats for Videotape, 4.
[5] AV Preserve (2010) A Primer on Codecs for Moving Image and Sound Archives& 10 Recommendations for Codec Selection and Management, www.avpreserve.com/wp-content/…/04/AVPS_Codec_Primer.pdf, 1.
[6] FADGI (2014) Creating and Archiving Born Digital Video Part III. High Level Recommended Practices, http://www.digitizationguidelines.gov/guidelines/FADGI_BDV_p3_20141202.pdf, 24.
[7] Jean-Christophe Kummer, Peter Kuhnle and Sebastian Gabler (2015) ‘Broadcast Archives: Between Productivity and Preservation’, IASA Journal, vol 44, 35.
[8] Kummer et al, ‘Broadcast Archives: Between Productivity and Preservation,’ 38.
[9] David Bull (2014) Communicating Pictures, Academic Press, 435-437.
[10] Av Preserve, A Primer on Codecs for Moving Image and Sound Archives, 2.
[11] For more reflections on compression, check out this fascinating talk from software theorist Alexander Galloway. The more practically bent can download and play with VISTRA, a video compression demonstrator developed at the University of Bristol ‘which provides an interactive overview of the some of the key principles of image and video compression.
[12] ‘FADGI, Digital File Formats for Videotape, 11.
[13] Presto Centre, AV Digitisation and Digital Preservation TechWatch Report #3, https://www.prestocentre.org/, 9.
[14] Presto Centre, AV Digitisation and Digital Preservation TechWatch Report #3, 10-11.
Marvel at the people who put together the U-Matic web resource, for example, which has been online since 1999, a comprehensive outline of the different models in the U-Matic ‘family.’ The site also hosts ‘chat pages’ relating to Betamax, Betacam, U-Matic and V2000, which are still very much active, with archives dating back to 1999. For video tape nerds willing to trawl the depths of these forums, nuggets of machine maintenance wisdom await you.
International Association of Sound and Audiovisual Archives
Sometimes you need to turn to rigorous, peer-reviewed research in order to learn from AV archive specialists.
‘Established in 1969 in Amsterdam to function as a medium for international co-operation between archives that preserve recorded sound and audiovisual documents’, IASA holds expertise relating to the many different and specialist issues attached to the care of AV archives.
Comprised of several committees dealing with issues such as standards and best practices; National Archive policies; Broadcast archives; Technical Issues; Research Archives; Training and Education, IASA reflects the diverse communities of practice involved in this professional field.
Most of the key IASA publications are accessible to members only, and therefore remain behind a paywall. It is definitely worth taking the plunge though, because there are comparably few specialist resources relating to AV archives written with an interdisciplinary—and international—audience in mind.
Examples of issues covered in member-only publications include Selection in Sound Archives, Decay of Polymers, Deterioration of Polymers and Ethical Principles for Sound and Audiovisual Archives.
The latest publication from the IASA Technical Committee, Handling and Storage of Audio and Video Carriers (2014) or TC05, provides detailed outlines of types of recording carriers, physical and chemical stability, environmental factors and ‘passive preservation,’ storage facilities and disaster planning.
The report comes with this important caveat:
‘TC 05 is not a catalogue of mere Dos and Don’ts. Optimal preservation measures are always a compromise between many, often conflicting parameters, superimposed by the individual situation of a collection in terms of climatic conditions, the available premises, personnel, and the financial situation. No meaningful advice can be given for all possible situations. TC 05 explains the principal problems and provides a basis for the archivist to take a responsible decision in accordance with a specific situation […] A general “Code of Practice” […] would hardly fit the diversity of structures, contents, tasks, environmental and financial circumstances of collections’ (6).
Member benefits
Being an IASA member gives Greatbear access to research and practitioner communities that enable us to understand, and respond to, the different needs of our customers.
Typically we work with a range of people such as individuals whose collections have complex preservation needs, large institutions, small-to-medium sized archives or those working in the broadcast industry.
Our main concern is reformatting the tapes you send us, and delivering high quality digital files that are appropriate for your plans to manage and re-use the data in the future.
If you have a collection that needs to be reformatted to digital files, do contact us to discuss how we can help.
Sometimes genuine rarities turn up at the Greatbear studio. Our recent acquisition of four reels of ‘missing, believed wiped’ test recordings of cult BBC TV show The Old Grey Whistle Test is one such example.
It is not only the content of these recordings that are interesting, but their form too, because they were made on 1” Type A videotape.
The 1″ Type A was ‘one of the first standardised reel-to-reel magnetic tape formats in the 1 inch (25 mm) width.’ In the US it had greatest success as an institutional and industrial format. It was not widely adopted in the broadcast world because it did not meet Federal Communications Commission (FCC) specifications for broadcast videotape formats—it was capable of 350 lines, while the NTSC standard was 525, PAL and SECAM were 625. (Note: upcoming conference ‘Standards, Disruptions and Values in Digital Culture and Communication‘ taking place November 2015).
According the VT Old Boys website, created by ex-BBC engineers in order to document the history of videotape used at the organisation, 2″ Quadruplex tape remained very much the norm for production until the end of the 1970s.
Yet the very existence of the Old Grey Whistle Test tapes suggests type A videotape was being used in some capacity in the broadcast world. Perhaps ADAPT, a project researching British television production technology from 1960-present, could help us solve this mystery?
From Type A, to Type B….
As these things go, type A was followed by Type B, with this model developed by the German company Bosch. Introduced in 1976, Type B was widely adopted in continental Europe, but not in UK and USA which gravitated toward the type C model, introduced by SONY/ Ampex, also in 1976. Type C then became the professional broadcast standard and was still being used well into the 1990s. It was able to record high quality composite video, and therefore had an advantage over component videos such as Betacam and MII that were ‘notoriously fussy and trouble-prone.‘ Type C also had fancy functions like still, shuttle, variable-speed playback and slow motion.
From a preservation assessment point of view, ‘one-inch open reel is especially susceptible to risks associated with age, hardware, and equipment obsolescence. It is also prone to risks common to other types of magnetic media, such as mould, binder deterioration, physical damage, and signal drop-outs.’
The Preservation Self-Assessment Programme advise that ‘this format is especially vulnerable, and, based on content assessment, it should be a priority for reformatting.’
AMPEX made over 30 SMPTE type A models, the majority of which are listed here. Yet the number of working machines we have access to today is few and far between.
In years to come it will be common for people to say ‘it takes four 1” Type A tape recorders to make a working one’, but remember where you heard the truism first.
Harvesting several of these hulking, table-top machines for spares and working parts is exactly how we are finding a way to transfer these rare tapes—further evidence that we need to take the threat of equipment obsolescence very seriously.
Deciding when to digitise your magnetic tape collections can be daunting.
The Presto Centre, an advocacy organisation working to help ‘keep audiovisual content alive,’ have a graphic on their website which asks: ‘how digital are our members?’
They chart the different stages of ‘uncertainty,’ ‘awakening’, ‘enlightenment’, ‘wisdom’ and ‘certainty’ that organisations move through as they appraise their collections and decide when to re-format to digital files.
Similarly, the folks at AV Preserve offer their opinion on the ‘Cost of Inaction‘ (COI), arguing that ‘incorporating the COI model and analyses into the decision making process around digitization of legacy physical audiovisual media helps organizations understand the implications and make well-informed decisions.’
They have even developed a COI calculator tool that organisations can use to analyse their collections. Their message is clear: ‘the cost of digitization may be great, but the cost of inaction may be greater.’
Digitising small-medium audiovisual collections
For small to medium size archives, digitising collections may provoke worries about a lack of specialist support or technical infrastructure. It may be felt that resources could be better used elsewhere in the organisation. Yet as we, and many other people working with audiovisual archives often stress, the decision to transfer material stored on magnetic tape has to be made sooner or later. With smaller archives, where funding is limited, the question of ‘later’ is not really a practical option.
Furthermore, the financial cost of re-formatting audiovisual archives is likely to increase significantly in the next five-ten years; machine obsolescence will become an aggravated problem and it is likely to take longer to restore tapes prior to transfer if the condition of carriers has dramatically deteriorated. The question has to be asked: can you afford not to take action now?
If this describes your situation, you might want to hear about other small to medium sized archives facing similar problems. We asked one of our customers who recently sent in a comparatively small collection of magnetic tapes to share their experience of deciding to take the digital plunge.
We are extremely grateful for Annaig from the Medical Mission Sisters for answering the questions below. We hope that it will be useful for other archives with similar issues.
1. First off, please tell us a little bit about the Medical Mission Sisters Archive, what kind of materials are in the collection?
The Medical Mission Sisters General Archives include the central archives of the congregation. They gather all the documents relating to the foundation and history of the congregation and also documents relating to the life of the foundress, Anna Dengel. The documents are mainly paper but there is a good collection of photographs, slides, films and audio documents. Some born digital documents are starting to enter the archives but they are still few.
2. As an archive with a modest collection of magnetic tapes, why did you decide to get the materials digitised now? Was it a question of resources, preservation concerns, access request (or a mixture of all these things!)
The main reason was accessibility. The documents on video tapes or audio tapes were the only usable ones because we still had machines to read them but all the older ones, or those with specific formats, where lost to the archives as there was no way to read them and know what was really on the tapes. Plus the Medical Mission Sisters is a congregation where Sisters are spread out on 5 continents and most of the time readers don’t come to the archives but send me queries by emails where I have to respond with scanned documents or digital files. Plus it was obvious that some of the tapes were degrading as that we’d better have the digitisation sooner than later if we wanted to still be able to read what was on them. Space and preservation was another issue. With a small collection but varied in formats, I had no resources to properly preserve every tape and some of the older formats had huge boxes and were consuming a lot of space on the shelves. Now, we have a reasonably sized collection of CDs and DVDs, which is easy to store in good conditions and is accessible everywhere as we can read them on computer here and I can send them to readers via email.
3. Digital preservation is a notoriously complex, and rapidly evolving field. As a small archive, how do you plan to manage your digital assets in the long term? What kinds of support, services and systems are your drawing on to design a system which is robust and resilient?
At the moment the digital collection is so small that it cannot justify any support service or system. So I have to build up my own home made system. I am using the archives management software (CALM) to enter data relating to the conservation of the CDs or DVDs, dates of creation, dates to check them and I plan to have regular checks on them and migrations or copies made when it will prove necessary.
4. Aside from the preservation issue, what are your plans to use the digitised material that Greatbear recently transferred?
It all depends on the content of the tapes. But I’ve already spotted a few documents of interest, and I haven’t been through everything yet. My main concern now is to make the documents known and used for their content. I was already able to deliver a file to one of the Sisters who was working on a person related to the foundation of the congregation, the most important document on her was an audio file that I had just received from Greatbear, I was able to send it to her. The document would have been unusable a few weeks before. I’ve come across small treasures, like a film, probably made by the foundress herself, which nobody was aware of. The Sisters are celebrating this year the 90th anniversary of their foundation. I plan to use as many audio or video documents as I can to support the events the archives are going to be involved into.
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What is illuminating about Annaig’s answers is that her archive has no high tech plan in place to manage the collection – her solutions for managing the material very much draw on non-digital information management practices.
The main issues driving the decision to migrate the materials are fairly common to all archives: limited storage space and accessibility for the user-community.
What lesson can be learnt from this? Largely, that if you are trained as an archivist, you are likely to already have the skills you need to manage your digital collection.
So don’t let the more bewildering aspects of digital preservation put you off. But do take note of the changing conditions for playing back and accessing material stored on magnetic tape. There will come a time when it will be too costly to preserve recordings on a wide variety of formats – many of such formats we can help you with today.
At the beginning of 2015, the British Library launched the landmark Save Our Sounds project.
The press release explained:
‘The nation’s sound collections are under threat, both from physical degradation and as the means of playing them disappear from production. Archival consensus internationally is that we have approximately 15 years in which to save our sound collections by digitising them before they become unreadable and are effectively lost.’
Yes you have read that correctly dear reader: by 2030 it is likely that we simply will not be able to play many, if not all of the tape formats we currently support at Greatbear. A combination of machine obsolescence, tape deterioration and, crucially, the widespread loss of skills necessary to repair, service and maintain playback machines are responsible for this astounding situation. They will make it ‘costly, difficult and, in many cases, impossible’ to preserve our recorded audio heritage beyond the proposed cut-off date.
Yet whatever way you look at it, there is need to take action to migrate any collections currently stored on obsolete media, particular if you are part of a small organisation with limited resources. The reality is it will become more expensive to transfer material as we move closer to 2030. The British Library project relates particularly to audio heritage, but the same principles apply to audiovisual collections too.
Yes that rumbling you can hear is the sound of archivists the world over engaged in flurry of selection and appraisal activities….
Extinction
One of the most interesting things about discussions of obsolete media is that the question of operability is often framed as a matter of life or death.
Formats are graded according to their ‘endangered statuses’ in more or less explicit terms, as demonstrated on this Video Preservation website which offers the following ‘obsolescence ratings’:
‘Extinct: Only one or two playback machines may exist at specialist laboratories. The tape itself is more than 20 years old.
Critically endangered: There is a small population of ageing playback machinery, with no or little engineering or manufacturing support. Anecdotal evidence indicates that there are fewer working machine-hours than total population of tapes. Tapes may range in age from 40 years to 10 years.
Endangered: The machine population may be robust, but the manufacture of the machinery has stopped. Manufacturing support for the machines and the tapes becomes unavailable. The tapes are often less expensive, and more vulnerable to deterioration.
Threatened: The playback machines are available; however, either the tape format itself is unstable or has less integrity than other available formats, or it is known that a more popular or updated format will be replacing this one in a short period of time.
Vulnerable: This is a current but highly proprietary format.
Lower risk: This format will be in use over the next five years (1998-2002).’
The ratings on the video preservation website were made over ten years ago. A more comprehensive and regularly updated resource to consult is the Preservation Self-Assessment Program (PSAP), ‘a free online tool that helps collection managers prioritize efforts to improve conditions of collections. Through guided evaluation of materials, storage/exhibit environments, and institutional policies, the PSAP produces reports on the factors that impact the health of cultural heritage materials, and defines the points from which to begin care.’ As well as audiovisual media, the resource covers photo and image material, paper and book preservation. It also has advice about disaster planning, metadata, access and a comprehensive bibliography.
The good news is that fantastic resources do exist to help archivists make informed decisions about reformatting collections.
A Digital Compact Cassette
The bad news, of course, is that the problem faced by audiovisual archivists is a time-limited one, exacerbated no doubt by the fact that digital preservation practices on the ‘output end’ are far from stable. Finding machines to playback your Digital Compact Cassette collection, in other words, will only be a small part of the preservation puzzle. A life of file migrations in yet to be designed wrappers and content-management systems awaits all kinds of reformatted audiovisual media in their life-to-come as a digital archival object.
Depending on the ‘content value’ of any collection stored on obsolete media, vexed decisions will need to be made about what to keep and what to throw away at this clinical moment in the history of recorded sound.
Sounding the fifteen-year warning
At such a juncture, when the fifteen year warning has been sounded, perhaps we can pause for a second to reflect on the potential extinction of large swathes of audio visual memory.
If we accept that any kind of recording both contains memory (of a particular historical event, or performance) and helps us to remember as an aide-mémoire, what are the consequences when memory storage devices which are, according to UNESCO, ‘the primary records of the 20th and 21st centuries’, can no longer be played back?
These questions are of course profound, and emerge in response to what are consequential historical circumstances. They are questions that we will continue to ponder on the blog as we reflect on our own work transferring obsolete media, and maintaining the machines that play them back. There are no easy answers!
Perhaps we will come to understand the 00s as a point of audiovisual transition, when mechanical operators still functioned and tape was still in fairly good shape. When it was an easy, almost throw away decision to make a digital copy, rather than an immense preservation conundrum. So where once there was a glut of archival data—and the potential to produce it—is now the threat of abrupt and irreversible dropout.
Today it poses significant preservation problems, and is described by the Video Format Identification Guide as ‘endangered’: ‘the machine population may be robust, but the manufacture of the machinery has stopped. Manufacturing support for the machines and the tapes becomes unavailable. The tapes are often less expensive, and more vulnerable to deterioration.’
Our magnetic tape transfer aficionado and company director Adrian Finn explains that the format ‘feels and looks so far removed from most other video formats and for me restoring and replaying these still has a little “magic” when the images appear!’
What is one person’s preservation nightmare can of course become part of the artist’s supreme vision.
In an article on the BBC website Temple reflected on the recordings: ‘we affectionately called the format “Glorious Bogroll Vision” but really it was murksville. Today monochrome footage would be perfectly graded with high-contrast effects. But the 1970s format has a dropout-ridden, glitchy feel which I enjoy now.’
Note the visible drop out in the image
The glitches of 1/2″ video were perfect for Temple’s film, which aimed to capture the apocalyptic feeling of Britain on the eve of 1977. Indeed, Temple reveals that ‘we cut in a couple of extra glitches we liked them so much.‘
Does the cutting in of additional imperfection signal a kind-of fetishisation of the analogue video, a form of wanton nostalgia that enables only a self-referential wallowing on a time when things were gloriously a lot worse than they are now?
Perhaps the corrupted image interrupts the enhanced definition and clarity of contemporary digital video.
Indeed, Temple’s film demonstrates how visual perception is always produced by the transmission devices that playback moving images, sound and images, whether that be the 1/2″ video tape or the super HD television.
It is reminder, in other words, that there are always other ways of seeing, and underlines how punk, as a mode of aesthetic address in this case, maintains its capacity to intervene into the business-as-usual ordering of reality.
What to do with your 1/2″ video tapes?
While Temple’s film was made to look worse than it could have been, EIAJ 1/2″ video tapes are most definitely a vulnerable format and action therefore needs to be taken if they are to be preserved effectively.
In a week where the British Library launched their Save Our Sounds campaign, which stated that ‘archival consensus internationally is that we have approximately 15 years in which to save our sound collections by digitising them before they become unreadable and are effectively lost,’ the same timeframes should be applied to magnetic tape-based video collections.
So if your 1/2″ tapes are rotting in your shed as Temple’s Clash footage was, you know that you need to get in there, fish them out, and send them to us pronto!
This article is inspired by a collection of DVCAM tapes sent in by London-based cultural heritage organisation Sweet Patootee. Below we will explore several issues that arise from the transfer of DVCAM tapes, one of the many Digital Video formats that emerged in the mid-1990s. A second article will follow soon which focuses on the content of the Sweet Patootee archive, which is a fascinating collection of video-taped oral histories of 1 World War veterans from the Caribbean.
The main issue we want to explore below is the role error correction coding performs both in the composition of the digital video signal and during the preservation playback. We want to highlight this issue because it is often assumed that DVCAM, which first appeared on the market in 1996, is a fairly robust format.
The work we have done to transfer tapes to digital files indicates that error correction coding is working overdrive to ensure we can see and hear these recordings. The implication is that DVCAM collections, and wider DV-based archives, should really be a preservation priority for institutions, organisations and individuals.
Before we examine this in detail, let’s learn a bit about the technical aspects of error correction coding.
Error error error
Error correction coding is a staple part of audio and audio-visual digital media. It is of great important in the digital world of today where the higher volume of transmitted signals require greater degrees of compression, and therefore sophisticated error correction schemes, as this article argues.
Error correction works through a process of prediction and calculation known as interpolation or concealment. It takes an estimation of the original recorded signal in order to re-construct parts of the data that have been corrupted. Corruption can occur due either to wear and tear, or insufficiencies in the original recorded signal.
‘With any error protection system, if too many erroneous bits occur in the same sample, there is a risk of the error detection system failing, and in practice, most media failures (such as dropouts on tape or dirt on a CD), will result in a large chunk of data being lost, not just the odd data bit here and there. So a technique called interleaving is used to scatter data around the medium in such a way that if a large section is lost or damaged, when the data is reordered many smaller, manageable data losses are formed, which the detection and correction systems can hopefully deal with.’
Digital technology’s error correction is one of the key things that differentiate it from their analogue counterparts. As the IASA‘s Guidelines on the Production and Preservation of Digital Audio Objects (2009) explains:
‘Unlike copying analogue sound recordings, which results in inevitable loss of quality due to generational loss, different copying processes for digital recordings can have results ranging from degraded copies due to re-sampling or standards conversion, to identical “clones” which can be considered even better (due to error correction) than the original.’ (65)
To think that digital copies can, at times, exceed the quality of the original digital recording is both an astonishing and paradoxical proposition. After all we are talking about a recording that improves at the perceptual level, despite being compositionally damaged. It is important to remember that error correction coding cannot work miracles, and there are limits to what it can do.
Dietrich Schüller and Albrecht Häfner argue in the International Association of Sound and Audiovisual Archives’s (IASA) Handling and Storage of Audio and Video Carriers (2014) that ‘a perfect, almost error free recording leaves more correction capacity to compensate for handling and ageing effects and, therefore, enhances the life expectancy.’ If a recording is made however ‘with a high error rate, then there is little capacity left to compensate for further errors’ (28-29).
The bizarre thing about error-correction coding then is the appearance of clarity it can create. And if there are no other recordings to compare with the transferred file, it is really hard to know what the recorded signal is supposed to look and sound like were its errors not being corrected.
When we watch the successfully migrated, error corrected file post-transfer, it matters little whether the original was damaged. If a clear signal is transmitted with high levels of error correction, the errors will not be transferred, only the clear image and sound.
Contrast this with a damaged analogue tape it would be clearly discernible on playback. The plus point of analogue tape is they do degrade gracefully: it is possible to play back an analogue tape recording with real physical deterioration and still get surprisingly good results.
Digital challenges
The big challenge working with any digital recordings on magnetic tape is to know when a tape is in poor condition prior to playback. Often tape will look fine and, because of error correction, will sound fine too until it stops working entirely.
How then did we know that the Sweet Patootee tapes were experiencing difficulties?
Professional DV machines such as our DVC PRO have a warning function that flashes when the error-correction coding is working at heightened levels. With our first attempt to play back the tapes we noticed that regular sections on most of the tapes could not be fixed by error correction.
The ingest software we use is designed to automatically retry sections of the tape with higher levels of data corruption until a signal can be retrieved. Imagine a process where a tape automatically goes through a playing-rewinding loop until the signal can be read. We were able to play back the tapes eventually, but the high level of error correction was concerning.
As this diagram makes clear, around 25% of the recorded signal in DVCAM is composed of subcode data, error detection and error correction.
DVCAM & Mis-alignment
It is not just the over-active error correction on DVCAMs that should send the alarm bells ringing.
Alan Griffiths from Bristol Broadcast Engineering, a trained SONY engineer with over 40 years experience working in the television industry, told us that early DVCAM machines pose particular preservation challenges. The main problem here is that the ‘mechanisms are completely different’ for earlier DVCAM machines which means that there is ‘no guarantee’ they will play back effectively on later models.
Recordings made on early DVCAM machines exhibit back tensions problems and tracking issues. This increases the likelihood of DV dropout on playback because a loss of information was recorded onto the original tape. The IASA confirm that ‘misalignment of recording equipment leads to recording imperfections, which can take manifold form. While many of them are not or hardly correctable, some of them can objectively be detected and compensated for.’
One possible solution to this problem, as with DAT tapes, is to ‘misalign’ the replay digital video tape recorder to match the misaligned recordings. However ‘adjustment of magnetic digital replay equipment to match misaligned recordings requires high levels of engineering expertise and equipment’ (2009; 72), and must therefore not be ‘tried at home,’ so to speak.
Our experience with the Sweet Patootee tapes indicates that DVCAM tapes are a more fragile format than is commonly thought, particularly if your DVCAM collection was recorded on early machines. If you have a large collection of DVCAM tapes we strongly recommend that you begin to assess the contents and make plans to transfer them to digital files. As always, do get in touch if you need any advice to develop your plans for migration and preservation.
We have recently transferred a number of recordings of the poet, Anthony Rye, reading his work. The tapes were sent by his Grandson Gabriel who was kind enough to tell us a bit more about Anthony’s life and work.
The Rye family has been here since the end of the 19th century and Anthony came to live here in the 1940s with his wife, in the house I now live in.
Among his books of poems are The Inn of the Birds (1947),Poems from Selborne (1961) and To A Modern Hero (1957). He was an illustrator and trained as an engraver and illustrated The Inn of the Birds himself, of which he said the poems “…were written to make people more alive to the spirit of bird-life and to the nature of birds generally. It was hoped to communicate something of the intense pleasure in birds felt by the author, and at the same time, by emphasizing their strange remote quality without destroying the sense of their being our fellow creatures…”
His poem ‘The Shadow on the Lyth’ from Poems from Selborne, invokes a dark moment in Selborne’s history when it was proposed by the council to put a much needed sewage works at the bottom of Church Meadow, thus ruining one of the most beautiful settings in Hampshire – one beloved of natural historian Gilbert White. Anthony Rye fought this and after a long struggle managed to have the works re-sited out of sight.’
Gilbert White’s life and work was a significant influence on Rye’s work and in 1970 he published the book Gilbert White and his Selborne.
Although the BBC has previously broadcast Rye’s poems, Gabriel tell us that these particular recordings have not been. Until now the recordings have been stored in Arthur’s house; migrating them to digital files is an exciting opportunity for family members, but also hopefully wider audiences, to access Rye’s work.
Listen to Anthony Rye reading his poems, with thanks to Gabriel for granting permission
Recording technologies in history
Arthur Jolland, a nature photographer and friend of the poet made the recordings on a SONY 800B, a portable reel-to-reel tape machine described by SONY as ‘compact, convenient and capable, a natural for both business and pleasure.’
Sahr Conway-Lanz explains that ‘room noise may constitute roughly one quarter of the total hours of recorded sound’ because tape machines recorded at the super slow speed of 15/16 of an inch per second ‘in order to maximize the recording time on each tape’ (547-549).
Decreasing the speed of a tape recording causes a uniform reduction in the linearity of response, resulting in more hiss and dropouts. If you listen to the recordings made by Nixon, it is pretty hard to discern what is being said without reference to the transcripts.
The transfer process
There were no big issues with the condition of the Anthony Rye tapes other than a small amount of loose binder shedding. This was easily solved by dry cleaning with pellon fabric prior to digitization.
Although in some cases playing back tapes on exactly the same machine as it was recorded on is desirable (particularly so with DAT transfers), we migrated the recordings using our SONY APR 5003.
Using a technically superior model, one of the few large format professional reel-to-reel machines SONY manufactured, mitigates the extent to which errors are added to the recording as part of the transfer process. Furthermore, the greater flexibility and control offered with the 5003 makes it easier to accurately replay tapes recorded on machines that had lower specifications.
Another slight adjustment was attaching longer leader tape to the front and end of the tape. This is because the Sony APR 5003 has a much longer tape path than the 800B, and if this isn’t done material can be lost from the beginning and end of the recording.
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The journeys we have been on above – from the natural history of a Hampshire village seen through the eyes of largely unknown poet to the Watergate scandal – is another example of the diverse technical, cultural and historical worlds that are opened up by the ‘mysterious little reddish-brown ribbon‘ and its playback mechanisms.
Since 2005, UNESCO have used the landmark to highlight the importance of audiovisual archives to ‘our common heritage’ which contain ‘the primary records of the 20th and 21st centuries.’ Increasingly, however, the day is used to highlight how audio and moving image archives are particularly threatened with by ‘neglect, natural decay to technological obsolescence, as well as deliberate destruction’.
Indeed, the theme for 2014 is ‘Archives at Risk: Much More to Do.’ The Swiss National Sound Archives have made this rather dramatic short film to promote awareness of the imminent threat to audiovisual formats, which is echoed by UNESCO’s insistence that ‘all of the world’s audiovisual heritage is endangered.’
As it is World Audiovisual Heritage Day, we thought it would be a good idea to take a look at some of the recent research and policy that has been collected and published relating to digitisation and digital preservation.
While the UNESCO anniversary is useful for raising awareness of the fragility of audiovisual mediums, what is the situation for organisations and institutions grappling with these challenges in practice?
The survey asked a range of organisations, institutions and collections to rank issues that are critical for the preservation of video collections. Respondents ‘identified the top three stumbling blocks in preserving video as:
Getting funding and other resources to start preserving video (18%)
Supporting appropriate digital storage to accommodate large and complex video files (14%)
Locating trustworthy technical guidance on video file formats including standards and best practices (11%)’
Interestingly in relation to the work we do at Great Bear, which often reveal the fragilities of digital recordings made on magnetic tape, ‘respondents report that analog/physical media is the most challenging type of video (73%) followed by born digital (42%) and digital on physical media (34%).’
It may well be that there is simply more video on analogue/ physical media than other mediums which can account for the higher response, and that archives are yet to grapple with the archival problem of digital video stored on physical mediums such as DVD and in particular, consumer grade DVD-Rs. Full details will be published on The Signal, the Library of Congress’ Digital Preservation blog, in due course.
Recent research – Digital Preservation Coalition (DPC)
Another piece of preliminary research published recently was the user consultation for the 2nd edition of the Digital Preservation Coalition’s Digital Preservation Handbook. The first edition of the Handbook was published in 2000 but was regularly updated throughout the 00s. The consultation precedes what will be a fairly substantial overhaul of the resource.
Many respondents to the consultation welcomed that a new edition would be published, stating that much content is now ‘somewhat outdated’ given the rapid change that characterises digital preservation as a technological and professional field.
Survey respondents ranked storage and preservation (1), standards and best practices (2) and metadata and documentation (3) as the biggest challenges involved in digital preservation, and therefore converge with the NDSA findings. It must be stressed, however, that there wasn’t a massive difference across all the categories that included issues such as compression and encryption, access and creating digital materials.
Some of the responses ranged from the pragmatic…
‘digital preservation training etc tend to focus on technical solutions, tools and standards. The wider issues need to be stressed – the business case, the risks, significant properties’ (16)
‘increasingly archives are being approached by community archive groups looking for ways in which to create a digital archive. Some guidance on how archive services can respond effectively and the issues and challenges that must be considered in doing so would be very welcome’ (16)
…to the dramatic…
‘The Cloud is a lethal method of storing anything other than in Lo Res for Access, and the legality of Government access to items stored on The Cloud should make Curators very scared of it. Most digital curators have very little comprehension of the effect of solar flares on digital collections if they were hit by one. In the same way that presently part of the new method of “warfare” is economic hacking and attacks on financial institutions, the risks of cyber attacks on a country’s cultural heritage should be something of massive concern, as little could demoralise a population more rapidly. Large archives seem aware of this, but not many smaller ones that lack the skill to protect themselves’ (17)
…Others stressed legal issues related to rights management…
‘recording the rights to use digital content and ownership of digital content throughout its history/ life is critical. Because of the efforts to share bits of data and the ease of doing so (linked data, Europeana, commercial deals, the poaching of lines of code to be used in various tools/ services/ products etc.) this is increasingly important.’ (17)
It will be fascinating to see how the consultation are further contextualised and placed next to examples of best practice, case studies and innovative technological approaches within the fully revised 2nd edition of the Handbook.
European Parliament Policy on Film Heritage
Our final example relates to the European Parliament and Council Recommendation on Film Heritage. The Recommendation was first decreed in 2005. It invited Member States to offer progress reports every two years about the protection of and access to European film heritage. The 4th implementation report was published on 2 October 2014 and can be read in full here.
The language of the recommendation very much echoes the rationale laid out by UNESCO for establishing World Audiovisual Heritage Day, discussed above:
‘Cinematography is an art form contained on a fragile medium, which therefore requires positive action from the public authorities to ensure its preservation. Cinematographic works are an essential component of our cultural heritage and therefore merit full protection.’
Although the recommendation relates to preservation of cinematic works specifically, the implementation report offers wide ranging insight into the uneven ways ‘the digital revolution’ has affected different countries, at the level of film production/ consumption, archiving and preservation.
The report gravely states that ‘European film heritage risks missing the digital train,‘ a phrase that welcomes a bit more explanation. One way to understand is that it describes how countries, but also Europe as a geo-political space, is currently failing to capitalise on what digital technologies can offer culturally, but also economically.
The report reveals that the theoretical promise of interoperable digital technologies-smooth trading, transmission and distribution across economic, technical and cultural borders-was hindered in practice due to costly and complex copyright laws that make the cross border availability of film heritage, re-use (or ‘mash-up’) and online access difficult to implement. This means that EU member states are not able to monetise their assets or share their cultural worth. Furthermore, this is further emphasised by the fact that ‘85% of Europe’s film heritage is estimated to be out-of-commerce, and therefore, invisible for the European citizen’ (37).
In an age of biting austerity, the report makes very clear that there simply aren’t enough funds to implement robust digitization and digital preservation plans: ‘Financial and human resources devoted to film heritage have generally remained at the same level or have been reduced. The economic situation has indeed pushed Member States to change their priorities’ (38).
There is also the issue of preserving analogue expertise: ‘many private analogue laboratories have closed down following the definitive switch of the industry to digital. This raises the question on how to maintain technology and know-how related to analogue film’ (13).
The report gestures toward what is likely to be a splitting archival-headache-to-come for custodians of born digital films: ‘resources devoted to film heritage […] continue to represent a very small fraction of resources allocated to funding of new film productions by all Member States’ (38). Or, to put it in numerical terms, for every €97 invested by the public sector in the creation of new films, only €3 go to the preservation and digitisation of these films. Some countries, namely Greece and Ireland, are yet to make plans to collect contemporary digital cinema (see opposite infographic).
Keeping up to date
It is extremely useful to have access to the research featured in this article. Consulting these different resources helps us to understand the nuts and bolts of technical practices, but also how different parts of the world are unevenly responding to digitisation. If the clock is ticking to preserve audiovisual heritage in the abrupt manner presented in the Swiss National Archives Film, the EU research in particular indicates that it may well be too late already to preserve a significant proportion of audiovisual archives that we can currently listen to and watch.
All that is left to say is: enjoy the Day for World Audiovisual Heritage! Treasure whatever endangered media species flash past your eyes and ears. Be sure to consider any practical steps you can take to ensure the films and audio recordings that are important to you remain operable for many years to come.
At Greatbear, we carefully restore and transfer to digital file all types of content recorded to Digital Audio Tape (DAT), and can support all sample rate and bit depth variations.
This post focuses on some of the problems that can arise with the transfer of DATs.
Indeed, at a meeting of audio archivists held in 1995, there was a consensus even then that DAT was not, and would never be, a reliable archival medium. One participant stated: ‘we have tapes from 1949 that sound wonderful,’ and ‘we have tapes from 1989 that are shot to hell.’ And that was nearly twenty years ago! What chances do the tapes have now?
A little DAT history
Before we explore that, let’s have a little DAT history.
SONY introduced Digital Audio Tapes (DATs) in 1987. At roughly half the size of an analogue cassette tape, DAT has the ability to record at higher, equal or lower sampling rates than a CD (48, 44.1 or 32 kHz sampling rate respectively) at 16 bit quantization.
Although popular in Japan, DATs were never widely adopted by the majority of consumer market because they were more expensive than their analogue counterparts. They were however embraced in professional recording contexts, and in particular for recording live sound.
It was recording industry paranoia, particularly in the US, that really sealed the fate of the format. With its threatening promise of perfect replication, DAT tapes were subject to an unsuccessful lobbying campaign by the Recording Industry Association of America (RIAA). RIAA saw DATs as the ultimate attack on copyright law and pressed to introduce the Digital Audio Recorder Copycode Act of 1987.
This law recommended that each DAT machine had a ‘copycode’ chip installed that could detect whether prerecorded copyrighted music was being replicated. The method employed a notch filter that would subtly distort the quality of the copied recording, thus sabotaging acts of piracy tacitly enabled by the DAT medium. The law was however not passed, and compromises were made, although the US Audio Home Recording Act of 1992 imposed taxes on DAT machines and blank media.
How did they do ‘dat?
Like video tape recorders, DAT tapes use a rotating head and helical scan method to record data. The helical scan can, however, pose real problems for the preservation transfers of DAT tapes because it makes it difficult to splice the tape together if it becomes sticky and snaps during the tape wind. With analogue audiotape, which records information longitudinally, it is far more possible to splice the tape together and continue the transfer without risking irrevocable information loss.
Another problem posed by the helical scan method is that such tapes are more vulnerable to tape pack and backing deformation, as the CLIR guide explain:
‘Tracks are recorded diagonally on a helical scan tape at small scan angles. When the dimensions of the backing change disproportionately, the track angle will change for a helical scan recording. The scan angle for the record/playback head is fixed. If the angle that the recorded tracks make to the edge of the tape do not correspond with the scan angle of the head, mistracking and information loss can occur.’
When error correction can’t correct anymore
Most people will be familiar with the sound of digital audio dropouts even if they don’t know the science behind them. You will know them most probably as those horrible clicking noises produced when the error correction technology on CDs stops working. The clicks indicate that the ‘threshold of intelligibility’ for digital data has been breached and, as theorist Jonathan Sterne reminds us, ‘once their decay becomes palpable, the file is rendered entirely unreadable.’
Our SONY PCM 7030 professional DAT machine, pictured opposite, has a ‘playback condition’ light that flashes if an error is present. On sections of the tape where quality is really bad the ‘mute’ light can flash to indicate that the error correction technology can’t fix the problem. In such cases drop outs are very audible. Most DAT machines did not have such a facility however, and you only knew there was a problem when you heard the glitchy-clickety-crackle during playback when, of course, it was too late do anything about it.
The bad news for people with large, yet to be migrated DAT archives is that the format is ‘particularly susceptible to dropout. Digital audio dropout is caused by a non-uniform magnetic surface, or a malfunctioning tape deck. However, because the magnetically recorded information is in binary code, it results in a momentary loss of data and can produce a loud transient click or worse, muted audio, if the error correction scheme in the playback equipment cannot correct the error,’ the wonderfully informative A/V Artifact Atlas explains.
Given the high density nature of digital recordings on narrow magnetic tape, even the smallest speck of dust can cause digital audio dropouts. Such errors can be very difficult to eliminate. Cleaning playback heads and re-transferring is an option, but if the dropout was recorded at the source or the surface of tape is damaged, then the only way to treat irregularities is through applying audio restoration technologies, which may present a problem if you are concerned with maintaining the authenticity of the original recording.
Listen to this example of what a faulty DAT sounds like
Play back problems and mouldy DATs
Mould growth on the surface of DAT tape
A big problem with DAT transfers is actually being able to play back the tapes, or what is known in the business as ‘DAT compatibility.’ In an ideal world, to get the most perfect transfer you would play back a tape on the same machine that it was originally recorded on. The chances of doing this are of course pretty slim. While you can play your average audio cassette tape on pretty much any tape machine, the same cannot be said for DAT tapes. Often recordings were made on misaligned machines. The only solution for playback is, Richard Hess suggests, to mis-adjust a working machine to match the alignment of the recording on the tape.
As with any archival collection, if it is not stored in appropriate conditions then mould growth can develop. As mentioned above, DAT tapes are roughly half the size of the common audiocassette and the tape is thin and narrow. This makes them difficult to clean because they are mechanically fragile. Adapting a machine specifically for the purposes of cleaning, as we have done with our Studer machine, would be the most ideal solution. There is, however, not a massive amount of research and information about restoring mouldy DATs available online even though we are seeing more and more DAT tapes exhibiting this problem.
As with much of the work we do, the recommendation is to migrate your collections to digital files as soon as possible. But often it is a matter of priorities and budgets. From a technical point of view, DATs are a particularly vulnerable format. Machine obsolescence means that compared to their analogue counterparts, professional DAT machines will be increasingly hard to service in the long term. As detailed above, glitchy dropouts are almost inevitable given the sensitivity and all or nothing quality of digital data recorded on magnetic tape.
It seems fair to say that despite being meant to supersede analogue formats, DATs are far more likely to drop out of recorded sound history in a clinical and abrupt manner.
They therefore should be a high priority when decisions are made about which formats in your collection should be migrated to digital files immediately, over and above those that can wait just a little bit longer.
We have recently transferred a previously unpublished 3” ¼ inch tape recording of British 20th century composer Phyllis Tate’s Nocturn forFour Voices. The tape is a 2-track stereo recording made at 7.5 inches per second (in/s) at the Purcell Room in London’s Southbank Centre in 1975, and was broadcast on 16 September 1976.
Generally speaking, the faster the speed the better the reproduction quality when making the digital transfer. This is because higher tape speeds spread the recorded signal longitudinally over more tape area, therefore reducing the effects of dropouts and tape noise. The number of tracks recorded on the tape also has an impact on how good it sounds today. Simply put, the more information stored on the tape due to recording speed or track width, the better the transfer will sound.
The tape of Nocturn for Four Voices was however suffering from binder hydrolysis and therefore needed to be baked prior to play back. EMI tape doesn’t normally do this but as the tape was EMI professional it may well have used Ampex stock and / or have been back coated, thus making the binder more susceptible to such problems.
Remembering Phyllis Tate
Nocturn for Four Voices is an example of how Tate ‘composed for unusual combinations of instruments and voice.’ The composition includes ‘Bass Clarinet, Celeste, String Quartet and Double Bass’, music scholar Jane Ballantyne explains.
The tape was brought into us by Tate’s daughter, Celia Frank, who is currently putting the finishing touches to a web archive that, she hopes, will help contemporary audiences (re)discover her mother’s work.
Like many women musicians and artists, Phyllis Tate, who trained at the Royal Academy of Music, remains fairly obscure to the popular cultural ear.
This is not to say, of course, that her work did not receive critical acclaim from her contemporaries or posthumously. Indeed, it is fair to say that she had a very successful composing career. Both the BBC and the Royal Academy of Music, among others, commissioned compositions from Tate, and her work is available to hire or buy from esteemed music publishers Oxford University Press (OUP).
Edmund Whitehouse, who wrote a short biography of the composer, described her as ‘one of the outstanding British composers of her generation, she was truly her own person whose independent creative qualities produced a wide range of music which defy categorisation.’
Her music often comprised of contrasting emotional registers, lyrical sections and unexpected changes of direction. As a writer of operattas and choral music, with a penchant for setting poetry to music, her work is described by the OUP as the product of ‘an unusual imagination and an original approach to conventional musical forms or subjects, but never to the extent of being described as “avant-garde”.’
Tate’s music was very much a hit with iconic suffrage composer Ethel Smyth who, upon hearing Tate’s compositions, reputedly declared: ‘at last, I have heard a real woman composer.’ Such praise was downplayed by Tate, who tended to point to Smyth’s increased loss of hearing in later life as the cause of her enjoyment: ‘My Cello Concerto was performed soon afterwards at Bournemouth with Dame Ethel sitting in the front row banging her umbrella to what she thought was the rhythm of the music.’
While the dismissal of Smyth’s appreciation is tender and good humoured, the fact that Tate destroyed significant proportions of her work does suggest that at times she could have doubted her own abilities as a composer. Towards the end of her life she revealed: ‘I must admit to having a sneaking hope that some of my creations may prove to be better than they appear. One can only surmise and it’s not for the composer to judge. All I can vouch is this: writing music can be hell; torture in the extreme; but there’s one thing worse; and that is not writing it.’ As a woman composing in an overwhelmingly male environment, such hesitancies are perhaps an understandable expression of what literary scholars Gilbert and Gubar called ‘the anxiety of authorship.’
Tate’s work is a varied and untapped resource for those interested in twentieth century composition and the wider history of women composers. We wish Celia the best of luck in getting the website up and running, and hope that many more people will be introduced to her mother’s work as a consequence.
Thanks to Jane Ballantyne and Celia Frank for their help in writing this article.
At the recent Supernormal experimental arts and music festival held at Braziers Park, Oxfordshire, a number of artists were using analogue technologies to explore concepts that dovetail nicely with the work we do at Greatbear collecting, servicing and repairing obsolete tape machines.
Hacker Farm, for example, keep ‘obsolete tech and discarded, post-consumerist debris’ alive using ‘salvaged and the hand-soldered’ DIY electronics. Their performance was a kind-of technological haunting, the sound made when older machines are turned on and re-purposed in different eras. Eerie, decayed, pointless and mournful, the conceptual impetus behind Hacker Farm raises many questions that emerge from the rather simple desire to keep old technologies working. Such actions soon become strange and aesthetically challenging in the contemporary technological context, which actively reproduces obsolescence in the endless search for the new, fostering continuous wastefulness at the centre of industrial production.
Music by the Metre
Another performance at the festival which engaged with analogue technologies was Graham Dunning’s Music by the Metre. The piece pays homage to SituationistPinot-Gallizio‘s method of ‘Industrial Painting’ (1957-1959), in which the Italian artist created a 145 metre hand and spray painted canvas that was subsequently cut up and sold by the metre. The action, which attempted to destroy the perception of the sacrilegious art-object and transform it into something which could be mass-quantified and sold, aimed to challenge ‘the mental disease of banalisation’ inherent to what Guy Debord termed ‘the society of the spectacle.’
In Dunning’s contemporary piece he used spools of open reel tape to record a series of automated machines comprised of looping record players, synth drone, live environmental sound and tape loops. This tape is then cut by the artist in metre long segments, placed in see-through plastic bags and ‘sold’ on his temporary market stall used to record and present the work.
Dunning’s work exists in interesting tension with the ideas of Pinot-Gallizio, largely because of the different technological and aesthetic contexts the artists are responding to.
Pinot-Gallizio’s industrial painting aimed to challenge the role of art within a consumer society by accelerating its commodity status (mass-produced, uniform, quantified, art as redundant, art as part of the wall paper). Within Dunning’s piece, such a process of acceleration is not so readily available, particularly given the deep obsolescence of consumer-grade open reel tape in 2014, and, furthermore, its looming archival obsolescence (often cited at ’10-20 years‘ by archivists).
Within the contemporary context, open reel analogue tapes have become ornate and aestheticised in themselves because they have lost their function as an everyday, recordable mass blank media. When media lose their operating context they are transformed into objects of fascination and desire, as Claire Bishop pithily states in her Art Forum essay, ‘The Digital Divide’: ‘Today, no exhibition is complete without some form of bulky, obsolete technology—the gently clucking carousel of the slide-projector, or the whirring of an 8mm or 16mm film reel […] the sumptuous texture of indexical media is unquestionably seductive, but its desirability also arises from the impression that it is scarce, rare and precious.’
In reality, the impression of open reel to reel analogue tape’s rarity is however well justified, as manufacturers and distributors of magnetic tape are increasingly hard to find. Might there be something more complex and contradictory be going on in Dunning’s homage to Pinot-Gallizio? Could we understand it as a neat inversion of the mass-metred-object, doubly cut adrift from its historical (1950s-1970s) and technological operating context (the open reel tape recorder), the bag of tape is decelerated, existing as nothing other than art object. Stuffed messily in a plastic bag and displayed ready to be sold (if only by donation), the tape is both ugly and useless given its original and intended use. It is here Dunning’s and Pinot-Gallizio’s work converge, situated at different historical and temporal poles from which critique of the consumer society can be mounted: accelerated plenitude and decelerated exhaustion.
Analogue attachments
As a company that works with obsolete magnetic tape-based media, Greatbear has a vested interest in ensuring tapes and playback machines remain operational. Although our studio, with its stacks of long-forgotten machines, may look like a curious art installation to some, the tapes we migrate to digital files are not quite art objects…yet. Like Hacker Farm, we help to keep old media alive through careful processes of maintenance and repair.
From looking at how contemporary sound artists are engaging with analogue technologies, it is clear that the medium remains very much part of the message, as Marshall McLuhan would say, and that meaning becomes amplified, contorted or transformed depending on historical context, and media norms present within it.
Written in an engaging style, the report is well worth a read. If you don't have time, however, here are some choice selections from the report which relate to the work we do at Greatbear, and some of the wider topics that have been discussed on the blog.
'there are no unexpected changes in file sizes or formats on the horizon, but it is fair to say that the inexorable increase in file size will continue unabated […] Higher image resolutions, bits per pixel and higher frame rates are becoming a fact of life, driving the need for file storage capacity, transfer bandwidth and processing speeds, but the necessary technology developments continue to track some form of Moore’s law, and there is no reason to believe that the technical needs will exceed technical capability, although inevitably there will be continuing technology updates needed by archives in order for them to manage new material.'
Having pointed out the inevitability of file expansion, however, others parts of the report clearly express the very real everyday challenges that ever increasing file sizes are posing to the transmission of digital information between across different locations:
'transport of content was raised by one experienced archive workflow provider. They maintained that, especially with very high bit-rate content (such as 4k) it still takes too long to transfer files into storage over the network, and in reality there are some high-capacity content owners and producers shipping stacks of disks around the country in Transit vans, on the grounds that, in the right circumstances this can still be the highest bandwidth transfer mechanism, even though the Digital Production Partnership (DPP) are pressing for digital-only file transfer.'
While those hoards of transit vans zipping up and down the motorway between different media providers is probably the exception rather than the rule, we should note that a similar point was raised by Per Platou when he talked about the construction of the Videokuntstarkivet - the Norwegian video art archive. Due to the size of video files in particular, Per found that publishing them online really pushed server capabilities to the absolute maximum. This illustrates that there remains a discrepancy between the rate at which broadcast technologies develop and the economic, technological and ecological resources available to send and receive them.
Another interesting point about the move from physical to file-based media is the increased need for Quality-Control (QC) software tools that will be employed to 'ensure that our digital assets are free from artefacts or errors introduced by encoders or failures of the playback equipment.' Indeed, given that glitches born from slow or interrupted transfers may well be inevitable because of limited server capabilities, software developed by Bristol-based company Vidcheck will be very useful because it 'allows for real-time repair of Luma, Chroma, Gamma and audio loudness issues that may be present in files. This is a great feature given that many of the traditional products on the market will detect problems but will not automatically repair them.'
Other main points worth mentioning from the report is the increasing move to open-source, software only solutions for managing digital collections and the rather optimistic tone directed toward 'archives with specific needs who want to find a bespoke provider who can help design, supply and support a viable workflow option – so long as they avoid the large, proprietary ‘out-of-the-box’ solutions.'
The Library of Congress’s digital preservation blog The Signal is a regular reading stop for us, largely because it contains articles and interviews that impressively meld theory and practice, even if it does not exclusively cover issues relating to magnetic tape.
What is particularly interesting, and indeed is a feature of the keynotes for the Digital Preservation 2014 conference, is how the relationship between academic theory—especially relating to aesthetics and art—is an integral part of the conversation of how best to meet the challenge of digital preservation in the US. Keynote addresses from academics like Matthew Kirschenbaum (author of Mechanisms) and Shannon Mattern, sit alongside presentations from large memory institutions and those seeking ways to devise community approaches to digital stewardship.
The relationship between digital preservation and aesthetics is also a key concern of Richard Rhinehart and Jon Ippolito’s new book Re-Collection: Art, New Media and Social Memory, which has just been published by MIT Press.
This book, if at times deploying rather melodramatic language about the ‘extinction!’ and ‘death!’ of digital culture, gently introduces the reader to the wider field of digital preservation and its many challenges. Re-Collection deals mainly with born-digital archives, but many of the ideas are pertinent for thinking about how to manage digitised collections as well.
In particular, the recommendation by the authors that the digital archival object remains variable was particularly striking: ‘the variable media approach encourages creators to define a work in medium- independent terms so that it can be translated into a new medium once its original format is obsolete’ (11). Emphasising the variability of the digital media object as a preservation strategy challenges the established wisdom of museums and other memory institutions, Rhinehart and Ippolito argue. The default position to preserve the art work in its ‘original’ form effectively freezes a once dynamic entity in time and space, potentially rendering the object inoperable because it denies works of art the potential to change when re-performed or re-interpreted. Their message is clear: be variable, adapt or die!
As migrators of tape-based collections, media variability is integral to what we do. Here we tacitly accept the inauthenticity of the digitised archival object, an artefact which has been allowed to change in order to ensure accessibility and cultural survival.
US/ European differences ?
While aesthetic and theoretical thinking is influencing how digital information management is practiced in the US, it seems as if the European approach is almost exclusively framed in economic and computational terms.
Consider, for example, the recent EU press release about the vision to develop Europe’s ‘knowledge economy‘. The plans to map and implement data standards, create cross-border coordination and an open data incubator are, it would seem, far more likely to ensure interoperable and standardised data sharing systems than any of the directives to preserve cultural heritage in the past fifteen years, a time period characterised by markedly unstable approaches, disruptive innovations and a conspicuous lack of standards (see also the E-Ark project).
‘Digital cultural heritage is dependent on some of the same systems, standards and tools used by the entire digital preservation community. Practitioners in the humanities, arts, and information and social sciences, however, are increasingly beginning to question common assumptions, wondering how the development of cultural heritage-specific standards and best practices would differ from those used in conjunction with other disciplines […] Most would agree that preserving the bits alone is not enough, and that a concerted, continual effort is necessary to steward these materials over the long term.’
Of course approaches to digital preservation and data management in the US are largely overdetermined by economic directives, and European policies do still speak to the needs of cultural heritage institutions and other public organisations.
What is interesting, however, is the minimal transnational cross pollination at events such as DigiPres, despite the globally networked condition we all share. This suggests there are subtle divergences between approaches to digital information management now, and how it will be managed in coming years across these (very large) geopolitical locations. Aesthetics or no aesthetics, the market remains imperative. Despite the turn toward open archives and re-usable data, competition is at the heart of the system and is likely to win out above all else.
Behind every tape (and every tape format) lie interesting stories, and the technological wizardry and international diplomacy that helped shape the roots of our digital audio visual world are worth looking into.
In 1976, when the green shoots of digital audio technology were emerging at industry level, the question of whether Video Tape Recorders (VTRs) could be digitised began to be explored in earnest by R & D departments based at SONY, Ampex and Bosch G.m.b.H. There was considerable scepticism among researchers about whether digital video tape technology could be developed at all because of the wide frequency required to transmit a digital image.
Several years of product development followed, shaped, in part, by competing regional preferences. As Jim Slater argues in Modern Television Systems (1991): 'much of the initial work towards digital standardisation was concerned with trying to find ways of coping with the three very different colour subcarrier frequencies used in NTSC, SECAM and PAL systems, and a lot of time and effort was spent on this' (114).
Establishing a standard sampling frequency did of course have real financial consequences, it could not be randomly plucked out the air: the higher the sampling frequency, the greater overall bit rate; the greater overall bit rate, the more need for storage space in digital equipment. In 1982, after several years of negotiations, a 13.5 MHz sampling frequency was agreed. European, North American, 'Japanese, the Russians, and various other broadcasting organisations supported the proposals, and the various parameters were adopted as a world standard, Recommendation 601 [a.k.a. 4:2:2 DTV] standard of the CCIR [Consultative Committee for International Radio, now International Telecommunication Union]' (Slater, 116).
The 4:4:2 DTV was an international standard that would form the basis of the (almost) exclusively digital media environment we live in today. It was 'developed in a remarkably short time, considering its pioneering scope, as the worldwide television community recognised the urgent need for a solid basis for the development of an all-digital television production system', write Stanley Baron and David Wood
Once agreed upon, product development could proceed. The first digital video tape, the D-1, was introduced on the market in 1986. It was an uncompressed component video which used enormous bandwidth for its time: 173 Mbit/sec (bit rate), with maximum recording time of 94 minutes.
BTS DCR 500 D-1 video recorder at Greatbear studio
As Slater writes: 'unfortunately these machines are very complex, difficult to manufacture, and therefore very expensive […] they also suffer from the disadvantage that being component machines, requiring luminance and colour-difference signals at input and output, they are difficult to install in a standard studio which has been built to deal with composite PAL signals. Indeed, to make full use of the D-1 format the whole studio distribution system must be replaced, at considerable expense' (125).
Being forced to effectively re-wire whole studios, and the considerable risk involved in doing this because of continual technological change, strikes a chord with the challenges UK broadcast companies face as they finally become 'tapeless' in October 2014 as part of the Digital Production Partnership's AS-11 policy.
Sequels and product development
As the story so often goes, D-1 would soon be followed by D-2. Those that did make the transition to D-1 were probably kicking themselves, and you can only speculate the amount of back injuries sustained getting the machines in the studio (from experience we can tell you they are huge and very heavy!)
It was fairly inevitable a sequel would be developed because even as the D-1 provided uncompromising image quality, it was most certainly an unwieldy format, apparent from its gigantic size and component wiring. In response a composite digital video, the D-2, was developed by Ampex and introduced in 1988.
In this 1988 promotional video, you can see the D-2 in action. Amazingly for our eyes and ears today the D-2 is presented as the ideal archival format. Amazing for its physical size (hardly inconspicuous on the storage shelf!) but also because it used composite video signal technology. Composite signals combine on one wire all the component parts which make up a video signal: chrominance (colour, or Red Green, Blue - RGB) and luminance (the brightness or black and white information, including grayscale).
While the composite video signal used lower bandwidth and was more compatible with existing analogue systems used in the broadcast industry of the time, its value as an archival format is questionable. A comparable process for the storage we use today would be to add compression to a file in order to save file space and create access copies. While this is useful in the short term it does risk compromising file authenticity and quality in the long term. The Ampex video is fun to watch however, and you get a real sense of how big the tapes were and the practical impact this would have had on the amount of time it took to produce TV programmes.
Enter the D-3
Following the D-2 is the D-3, which is the final video tape covered in this article (although there were of course the D5 and D9.)
The D-3 was introduced by Panasonic in 1991 in order to compete with Ampex's D-2. It has the same sampling rate as the D-2 with the main difference being the smaller shell size.
The D-3's biggest claim to fame was that it was the archival digital video tape of choice for the BBC, who migrated their analogue video tape collections to the format in the early 1990s. One can only speculate that the decision to take the archival plunge with the D-3 was a calculated risk: it appeared to be a stable-ish technology (it wasn't a first generation technology and the difference between D-2 and D-3 is negligible).
The extent of the D-3 archive is documented in a white paper published in 2008, D3 Preservation File Format, written by Philip de Nier and Phil Tudor: 'the BBC Archive has around 315,000 D-3 tapes in the archive, which hold around 362,000 programme items. The D-3 tape format has become obsolete and in 2007 the D-3 Preservation Project was started with the goal to transfer the material from the D-3 tapes onto file-based storage.'
It has then taken six years to migrate less than a third of the BBC's D-3 archive. Given that D-3 machines are now obsolete, it is more than questionable whether there are enough D-3 head hours left in existence to read all the information back clearly and to an archive standard. The archival headache is compounded by the fact that 'with a large proportion of the content held on LTO3 data tape [first introduced 2004, now on LTO-6], action will soon be required to migrate this to a new storage technology before these tapes become difficult to read.' With the much publicised collapse of the BBC's (DMI) digital media initiative in 2013, you'd have to very strong disposition to work in the BBC's audio visual archive department.
The roots of the audio visual digital world
The development of digital video tape, and the international standards which accompanied its evolution, is an interesting place to start understanding our current media environment. They are also a great place to begin examining the problems of digital archiving, particularly when file migration has become embedded within organisational data management policy, and data collections are growing exponentially.
While the D-1 may look like an alien-techno species from a distant land compared with the modest, immaterial file lists neatly stored on hard drives that we are accustomed to, they are related through the 4:2:2 sample rate which revolutionised high-end digital video production and continues to shape our mediated perceptions.
Preserving early digital video formats
More more information on transferring D-1, D-2, D3, D-5, D-5HD & D-9 / Digital S from tape to digital files, visit our digitising pages for:
We have recently digitised a U-matic video tape of eclectic Norwegian video art from the 1980s. The tape documents a performance by Kjartan Slettemark, an influential Norwegian/ Swedish artist who died in 2008. The tape is the ‘final mix’ of a video performance entitledChromakey Identity Blue in which Slettemark live mixed several video sources onto one tape.
The theoretical and practical impossibility of documenting live performance has been hotly debated in recent times by performance theorists, and there is some truth to those claims when we consider the encounter with Slettemark’s work in the Greatbear studio. The recording is only one aspect of the overall performance which, arguably, was never meant as a stand alone piece. A Daily Mail-esque reaction to the video might be ‘Eh? Is this art?! I don’t get it!’.
Having access to the wider context of the performance is sometimes necessary if the intentions of the artist are to be appreciated. Thankfully, Slettemark’s website includes part-documentation of Chromakey Identity Blue, and we can see how the different video signals were played back on various screens, arranged on the stage in front of (what looks like) a live TV audience.
Upon seeing this documentation, the performance immediately evokes to the wider context of 70s/ 80s video art, that used the medium to explore the relationship between the body, space, screen and in Slettemark’s case, the audience. A key part of Chromakey Identity Blue is the interruption of the audience’s presence in the performance, realised when their images are screened across the face of the artist, whose wearing of a chroma key mask enables him to perform a ‘special effect’ which layers two images or video streams together.
What unfolds through Slettemark’s performance is at times humorous, suggestive and moving, largely because of the ways the faces of different people interact, perform or simply ignore their involvement in the spectacle. As Marina Abramovic‘s use of presence testifies, there can be something surprisingly raw and even confrontational about incorporating the face into relational art. As an ethical space, meeting with the ‘face’ of another became a key concept for twentieth century philosopher Emmanuel Levinas. The face locates, Bettina Bergo argues, ‘“being” as an indeterminate field’ in which ‘the Other as a face that addresses me […] The encounter with a face is inevitably personal.’
If an art work like Slettemark’s is moving then, it is because it stages moments where ‘faces’ reflect and interface across each other. Faces meet and become technically composed. Through the performance of personal-facial address in the artwork, it is possible to glimpse for a brief moment the social vulnerability and fragility such meetings engender. Brief because the seriousness is diffused Chromakey Identity Blue by a kitsch use of a disco ball that the artist moves across the screen to symbolically change the performed image, conjuring the magical feel of new technologies and how they facilitate different ways of seeing, being and acting in the world.
Videokunstarkivet (The Norwegian Video Art Archive)
The tape of Slettemark was sent to us byVideokunstarkivet,an exciting archival project mapping all the works of video art that have been made in Norway since the mid-1960s. Funded by the Norwegian Arts Council, the project has built the digital archival infrastructure from the bottom up, and those working on it have learnt a good many things along the way. Per Platou, who is managing the project, was generous enough to share some the insights for readers of our blog, and a selection of images from archive’s interface.
There are several things to be considered when creating a digital archive ‘from scratch’. Often at the beginning of a large project it is possible look around for examples of best practice within your field. This isn’t always the case for digital archives, particularly those working almost exclusively with video files, whose communities of practice are unsettled and established ways of working few and far between. The fact that even in 2014, when digital technologies have been widely adopted throughout society, there is still not any firm agreement on standard access and archival file formats for video files indicates the peculiar challenges of this work.
Because of this, projects such as Videokunstarkivet face multiple challenges, with significant amounts of improvisation required in the construction of the project infrastructure. An important consideration is the degree of access users will have to the archive material. As Per explained, publicly re-publishing the archive material from the site in an always open access form is not a concern of the Videokunstarkivet, largely due to the significant administrative issues involved in gaining licensing and copyright permissions. ‘I didn’t even think there was a difference between collecting and communicating the work yet after awhile I saw there is no point in showing everything, it has to be filtered and communicated in a certain way.’
Instead, interested users will be given a research key or pass word which enables them to access the data and edit metadata where appropriate. If users want to re-publish or show the art in some form, contact details for the artist/ copyright holder are included as part of the entry. Although the Videokunstarkivet deals largely with video art, entries on individual artists include information about other archival collections where their material may be stored in order to facilitate further research. Contemporary Norwegian video artists are also encouraged to deposit material in the database, ensuring that ongoing collecting practices are built-in to the long-term project infrastructure.
Another big consideration in constructing an archive is what to collect. Per told me that video art in Norway really took off in the early 80s. Artists who incorporated video into their work weren’t necessarily specialists in the medium, ‘there just happened to be a video camera nearby so they decided to use it.’ Video was therefore often used alongside films, graphics, performance and text, making the starting point for the archive, according to Per, ‘a bit of a mess really.’ Nonetheless, Videokunstarkivet ‘approaches every artist like it was Edvard Munch,’ because it is very hard to know now exactly what will be culturally valuable in 10, 20 or even 100 years from now. While it may not be appropriate to ‘save everything!’ for larger archival projects, for a self-contained and focused archival project such as the Videokunstarkivet, an inclusive approach may well be perfectly possible.
Building software infrastructures
Another important aspect of the project is technical considerations – the actual building of the back/ front end of the software infrastructure that will be used to manage newly migrated digital assets.
It was very important that the Videokunstarkivet archive was constructed using Open Source software. It was necessary to ensure resilience in a rapidly changing technological context, and so the project could benefit from any improvements in the code as they are tested out by user communities.
The project uses an adapted version of Digital Asset Management system Resource Space that was developed with LIMA, an organisation based in Holland that preserves, distributes and researches media art. Per explained that ‘since Resource Space was originally meant for photos and other “light” media files, we found it not so well suited for our actual tasks.’ Video files are of course far ‘heavier’ than image or even uncompressed audio files. This meant that there were some ‘pretty severe’ technical glitches in the process of establishing a database system that could effectively manage and playback large, uncompressed master and access copies. Through establishing the Videokunstarkivet archive they were ‘pushing the limits of what is technically possible in practice’, largely because internet servers are not built to handle large files, particularly not if those files are being transcoding back and forth across the file management system. In this respect, the project is very much ‘testing new ground’, creating an infrastructure capable of effectively managing, and enabling people to remotely access large amounts of high-quality video data.
Access files will be available to stream using open source encoded files Web M (hi and lo) and X264 (hi and lo), ensuring that streaming conditions can be adapted to individual server capabilities. The system is also set up to manage change large-scale file transcoding should there be substantial change in file format preferences. These changes can occur without compromising the integrity of the uncompressed master file.
The interface is built with Bootstrap which has been adapted to create ‘a very advanced access-layer system’ that enables Videokunstarkivet to define user groups and access requirements. Per outlined these user groups and access levels as follows:
‘- Admin: Access to everything (i.e.Videokunstarkivet team members)
– Research: Researchers/curators can see video works, and almost all the metadata (incl previews of the videos). They cannot download master files. They can edit metadata fields, however all their edits will be visible for other users (Wikipedia style). If a curator wants to SHOW a particular work, they’ll have to contact the artist or owner/gallery directly. If the artist agrees, they (or we) can generate a download link (or transcode a particular format) with a few clicks.
– Artist: Artists can up/download uncompressed master files freely, edit metadata and additional info (contact, cv, websites etc etc). They will be able to use the system to store digital master versions freely, and transcode files or previews to share with who they want. The ONLY catch is that they can never delete a master file – this is of course coming out of national archive needs.’
Per approached us to help migrate the Kjartan Slettemark tape because of the thorough approach and conscientious methodology we apply to digitisation work. As a media archaeology enthusiast, Per stressed that it was desirable for both aesthetic and archival reasons that the materiality of U-matic video was visible in the transferred file. He didn’t want the tape, in other words, to be ‘cleaned up’ in anyway. To migrate the tape to digital file we used our standardised transfer chain for U-matic tape. This includes using an appropriate time-based-corrector contemporary to U-matic era, and conversion of the dub signal using a dedicated external dub – y/c converter circuit.
We are very happy to be working with projects such as the Videokunstarkivet. It has been a great opportunity to learn about the nuts and bolts design of cutting-edge digital video archives, as well as discover the work of Kjartan Slettemark, whose work is not well-known in the UK. Massive thanks must go to Per for his generous sharing of time and knowledge in the process of writing this article. We wish the Videokunstarkivet every success and hope it will raise the profile of Norwegian video art across the world.
This Studer is, however, different from the rest, because it originally belonged to BBC Bristol. It therefore bears the hallmarks of a machine specifically adapted for broadcast use.
The telltale signs can be found in customised features, such as control faders and switches. These enabled sound levels to be controlled remotely or manually.
The presence of peak programme meters (P.P.M.), buttons that made it easy to see recording speeds (7.5/ 15 inches per second), as well as switches between cues and channels, were also specific to broadcast use.
Studer tape machines were favoured in professional contexts because of their ‘sturdy tape transport mechanism with integrated logic control, electronically controlled tape tension even during fast wind and braking phases, electronic sensing of tape motion and direction, electronic tape timing, electronic speed control, plug-in amplifier modules with separately plug-gable equalization and level pre-sets plus electronic equalization changeover.’
Because of Studer’s emphasis on engineering quality, machines could be adapted according to the specific needs of a recording or broadcast project.
For our ¼ inch reel-to-reel digitisation work at Greatbear, we have also adapted a Studer machine to clean damaged or shedding tapes prior to transfer. The flexibility of the machine enables us to remove fixed guides so vulnerable tape can move safely through the transport. This preservation-based adaption is testimony to the considered design of Studer open reel tape machines, even though it diverges from its intended use.
If you want to learn a bit more about the Equipment department at the BBC who would have been responsible for adapting machines, follow this link.
Generational change for digital technologies are rapid and disruptive. ‘In the digital context the next generation may only be five to ten years away!’ Tom Gollins from the National Archives reminds us, and this seems like a fairly conservative estimate.
It can feel like the rate of change is continually accelerating, with new products appearing all the time. It is claimed, for example, that the phenomena of ‘wearable tech chic’ is now upon us, with the announcement this week that Google’s glass is available to buy for £1,000.
The impact of digital technologies have been felt throughout society, and this issue will be explored in a large immersive exhibition of art, design, film, music and videogames held at the Barbian July-Sept 2014. It is boldly and emphatically titled: Digital Revolution.
To bring such technological transformations back into focus with our work at Greatbear, consider this 2004 brochure that recently re-surfaced in our Studio. As an example of the rapid rate of technological change, you need look no further.
Storage media such as Zip disks, Jaz Cart, Exabytes and hard drives that could store between 36-500Gb of data were also available to purchase.
RMGI are currently the only manufacturer of professional open reel audio tape. In the 2004 catalogue, different brands of open reel analogue tape are listed at a third of 2014 retail prices, taking into account rates of inflation.
While some of the products included in the catalogue, namely CDs, DVDs and open reel tape, have maintained a degree of market resiliency due to practicality, utility or novelty, many have been swept aside in the march of technological progress that is both endemic and epidemic in the 21st century.
We work with a range of customers at Greatbear, digitising anything from personal collections to the content of institutional archives. Because of this, what customers need from a digitisation service can be very different.
A key issue relates to the question of how much we process the digital file, both as part of the transfer and in post-production. In other words, to what extent do we make alterations to the form of the recording when it becomes a digitised artifact. While this may seem like an innocuous problem, the question of whether or not to apply processing, and therefore radically transform the original recording, is a fraught, and for some people, ethical, consideration.
There are times when applying processing technologies is desirable and appropriate. With the transfer of video tape, for example, we always use time-based correctors or frame synchronisers to reduce or eliminate errors during play back. Some better quality video tape machines, such as the U-matic BVU-950P, already have time-based correctors built in which makes external processing unnecessary. As the AV Artifact Atlas explains however, time-based correction errors are very common with video tape:
‘When a different VTR is used to playback the same signal, there can be slight mechanical and electronic differences that prevent the tape from being read in the same way it was written. Perhaps the motors driving the tape in a playback VTR move slightly slower than they did in the camera that recorded the tape, or maybe the head of the playback VTR rotates a fraction quicker than the video head in the machine that recorded the tape. These tiny changes in timing can dramatically affect stability in a video image.’
We also utilise built in processes that are part of machine’s circuitry, such as drop out compensation and noise reduction. We use these, however, not in order to make the tape ‘look better.’ We do it rather as a standard calibration set up, which is necessary for the successful playback of the tape in a manner appropriate to its original operating environment.
After all, video tape machines were designed to be interchangeable. It is likely such stabilising processing would have been regularly used to play back tapes in machines that were different to those they were recorded on. Time-based correction and frame synchronisation are therefore integral to the machine/ playback circuitry, and using such processing tools is central to how we successfully migrate tape-based collections to digital files.
Digital processing tools
Our visual environment has changed dramatically since the days when domestic video tape was first introduced, let alone since the hay day of VHS. The only certainty is that it will continue to change. Once it was acceptable for images to be a bit grainy and low resolution, now only the crisp clarity of a 4K Ultra HD image will do. There is perhaps the assumption that ‘clearer is better’, that being able to watch moving images in minute detail is a marker of progress. Yet should this principle be applied to the kinds of digitisation work we do at Great Bear? There are processors that can transform the questionable analogue image into a bright, high definition, colour enriched digital copy. The teranex processor, for example, ‘includes extremely high quality de-interlacing, up conversion, down conversion, SD and HD cross/standards conversion, automatic cadence detection and removal even with edited content, noise reduction, adjustable scaling and aspect ratio conversion.’ ‘Upgrading’ analogue images in this way does come with certain ethical risks.
Talking about ethics in conjunction with video or audio tape might seem a bit melodramatic, but it is at the point of intervention/ non-intervention where the needs of our customers diverge the most. This is not to say that people who do want to process their tapes are unethical – far from it! We understand that for some customers it may be preferable for such processing to occur, or to apply other editing techniques such as noise reduction or amplification, so that audio can be heard with greater clarity.
Instead we want to emphasise that our priority is getting the best out of the tape and our playback machines, rather than relying on the latest processing technology that is also at risk from obsolescence. After all, a heavily processed file will always require further processing at an unknown point in future so that it can maintain visually relevant to whatever format is commercially dominant at the time. Such transformations of the digital file, which are necessarily destructive and permanent, contribute to the further circulation of what Hito Steyerl calls ‘poor images‘, ‘a rag or a rip; an AVI or a JPEG…The poor image has been uploaded, downloaded, shared, reformatted, and reedited. It transforms quality into accessibility, exhibition value into cult value, films into clips, contemplation into distraction.’
Maintaining the integrity, and as far as possible authenticity of the original recordings, is a core part of our methodology. In this way our approach corresponds with Jisc’s mantra of ‘reproduction not optimisation’ where they write:
‘Improving, altering or modifying media for optimisation may seem logical when presenting works to a public or maintaining perceived consistency. It should be remembered that following an often natural inclination to enhance what we perceive to be a poor level of quality is a subjective process prescribed by personal preference, technological trends and cultural influences. In many cases the intentions of a creator are likely to be unknown and this can cause difficulties in interpreting levels of quality. In these instances common sense alongside trepidation should prevail. On the one end of the spectrum unintelligible recordings may be of little use to anyone, whereas at the opposite end recordings from previous eras were not produced with modern standards of clarity in mind.’
It is important to bear in mind, however, that even if a file is subject to destructive editing there may come a time when the metadata created about the artefact can help to illuminate its context and provenance, and therefore help it maintain its authenticity. The debates regarding digital authenticity and archiving will of course shift as time passes and practices evolve.
In the meantime, we will continue to do what we are most skilled at: restoring, repairing and migrating magnetic tape to digital files in a manner that maintains both the integrity of the original operating environment and the recorded signal.
‘there is consensus internationally that we as archivists have a 10-20 year window of opportunity in which to migrate the content of our physical sound collections to stable digital files. After the end of this 10-20 year window, general consensus is that the risks faced by physical media mean that migration will either become impossible or partial or just too expensive.’
This point of view certainly corresponds to our experience at Greatbear. As collectors of a range of domestic and professional video and audio tape playback machines, we are aware of the particular problems posed by machine obsolescence. Replacement parts can be hard to come by, and the engineering expertise needed to fix machines is becoming esoteric wisdom. Tape degradation is of course a problem too. These combined factors influence the shortened horizon of magnetic tape-based media.
IRENE (Image, Reconstruct, Erase Noise, Etc.), developed by physicist Carl Haber at the Lawrence Berkeley National Laboratory, is a software programme that ‘photographs the grooves in fragile or decayed recordings, stitches the “sounds” together with software into an unblemished image file, and reconstructs the “untouchable” recording by converting the images into an audio file.’
The programme was developed by Haber after he heard a radio show discuss the Library of Congress’ audio collections that were so fragile they risked destruction if played back. Haber speculated that the insights gained from a project he was working on could be used to recover these audio recordings. ‘“We were measuring silicon, why couldn’t we measure the surface of a record? The grooves at every point and amplitude on a cylinder or disc could be mapped with our digital imaging suite, then converted to sound.”’
For those involved in the development of IRENE, there was a strong emphasis on the benefits of patience and placing trust in the inevitable restorative power of technology. ‘It’s ironic that as we put more time between us and the history we are exploring, technology allows us to learn more than if we had acted earlier.’
Can such a hands-off approach be applied to magnetic tape based media? Is the 10-20 year window of opportunity described by Tovell above unnecessarily short? After all, it is still possible to playback wax cylinder recordings from the early 20th century which seem to survive well over long periods of time, and magnetic tape is far more durable than is commonly perceived.
In a fascinating audio recording made for the Pitt Rivers Museum in Oxford, Nigel Bewley from the British Library describes how he migrated wax cylinder recordings that were made by Evans Pritchard in 1928-1930 and Diamond Jenness in 1911-1912. Although Bewley reveals his frustration in the preparation process, he reveals that once he had established the size of stylus and rotational speed of the cylinder player, the transfer was relatively straightforward.
You will note that in contrast with the recovery work made possible by IRENE, the cylinder transfer was made using an appropriate playback mechanism, examples of which can accessed on this amazing section of the British Library’s website (here you can also browse through images and information about disc cutters, magnetic recorders, radios, record players, CD players and accessories such as needle tins and headphones – a bit of a treasure trove for those inclined toward media archaeology).
Perhaps the development of the IRENE technology will mean that it will no longer be necessary to use such ‘authentic’ playback mechanisms to recover information stored on obsolete media. This brings us neatly to the question of emulation.
Emulation
If we assume that all the machines that play back magnetic tape become irrevocably obsolete in 10-20 years, what other potential extraction methods may be available? Is it possible that emulation techniques, commonly used in the preservation of born-digital environments, can be applied to recover the recorded information stored on magnetic tape?
‘Emulation is a concept in digital preservation to keep things, especially hardware architectures, as they were. As the hardware itself might not be preservable as a physical entity it could be very well preserved in its software reproduction. […] For memory institutions old digital artifacts become more easy to handle. They can be viewed, rendered and interacted-with in their original environments and do not need to be adapted to our modern ones, saving the risk of modifying some of the artifact’s significant properties in an unwanted way. Instead of trying to mass-migrate every object in the institution’s holdings, objects are to be handled on access request only, significantly shifting the preservation efforts.’
For the sake of speculation, let us imagine we are future archaeologists and consider some of the issues that may arise when seeking to emulate the operating environments of analogue-based tape media.
To begin with, without a working transport mechanism which facilitates the transmission of information, the emulation of analogue environments will need to establish a circuitry that can process the Radio Frequency (RF) signals recorded on magnetic tape. As Jonathan Sterne reflects, ‘if […] we say we have to preserve all aspects of the platform in order to get at the historicity of the media practice, that means archival practice will have to have a whole new engineering dimension to it.’
Yet with the emulation of analogue environments, engineering may have to be a practical consideration rather than an archival one. For example, some kind of transport mechanism would presumably have to be emulated through which the tape could be passed through. It would be tricky to lay the tape out flat and take samples of information from its surface, as IRENE’s software does to grooved media, because of the sheer length of tape when it unwound. Without an emulated transport mechanism, recovery would be time consuming and therefore costly, a point that Tovell intimates at the beginning of the article. Furthermore, added time and costs would necessitate even more complex selection and appraisal decisions on behalf of archivists managing in-operative magnetic tape-based collections. Questions about value will become fraught and most probably politically loaded. With an emulated transport mechanism, issues such as tape vulnerability and head clogs, which of course impact on current migration practices, would come into play.
Audio and video differences
On a technical level emulation may be vastly more achievable for audio where the signal is recorded using a longitudinal method and plays back via a relatively simple process. Audio tape is also far less propriety than video tape. On the SONY APR-5003V machine we use in the Greatbear Studio for example, it is possible to play back tapes of different sizes, speeds, brands, and track formations via adjustments of the playback heads. Such versatility would of course need to be replicated in any emulation environment.
The technical circuitry for playing back video tape, however, poses significantly more problems. Alongside the helical scan methods, which records images diagonally across the video tape in order to prevent the appearance of visible joints between the signal segments, there are several heads used to read the components of the video signal: the image (video), audio and control (synch) track.
Unlike audio, video tape circuitry is more propriety and therefore far less inter-operable. You can’t play a VHS tape on a U-Matic machine, for example. Numerous mechanical infrastructures would therefore need to be devised which correspond with the relevant operating environments – one size fits all would (presumably) not be possible.
A generic emulated analogue video tape circuit may be created, but this would only capture part of the recorded signal (which, as we have explored elsewhere on the blog, may be all we can hope for in the transmission process). If such systems are to be developed it is surely imperative that action is taken now while hardware is operative and living knowledge can be drawn upon in order to construct emulated environments in the most accurate form possible.
While hope may rest in technology’s infinite capacity to take care of itself in the end, excavating information stored on magnetic tape presents far more significant challenges when compared with recordings on grooved media. There is far more to tape’s analogue (and digital) circuit than a needle oscillating against a grooved inscription on wax, lacquer or vinyl.
The latter part of this article has of course been purely speculative. It would be fascinating to learn about projects attempting to emulate the analogue environment in software – please let us know if you are involved in anything in the comments below.
In Trevor Owen’s excellent blog post ‘What Do you Mean by Archive? Genres of Usage for Digital Preservers’, he outlines the different ways ‘archive’ is used to describe data sets and information management practices in contemporary society. While the article shows it is important to distinguish between tape archives, archives as records management, personal papers and computational archives, Owens does not include an archival ‘genre’ that will become increasingly significant in the years to come: the archival market.
The announcement in late April 2014 that SONY has developed a tape cartridge capable of storing 185 TB of data was greeted with much excitement throughout the teccy world. The invention, developed with IBM, is ‘able to achieve the high storage capacity by utilising a “nano-grained magnetic layer” consisting of tiny nano-particles’ and boasts the world’s highest areal recording density of 148 Gb/in.
The news generated such surprise because it signaled the curious durability of magnetic tape in a world thought to have ‘gone tapeless‘. For companies who need to store large amounts of data however, tape storage, usually in the form of Linear Tape Open Cartridges, has remained an economically sound solution despite the availability of file-based alternatives. Imagine the amount of energy required to power up the zettabytes of data that exist in the world today? Whatever the benefits of random access, that would be a gargantuan electricity bill.
Indeed, tape cartridges are being used more and more to store large amounts of data. According to the Tape Storage Council industry group, tape capacity shipments grew by 13 percent in 2012 and were projected to grow by 26 percent in 2013. SONY’s announcement is therefore symptomatic of the growing archival market which has created demand for cost effective data storage solutions.
‘This demand is being driven by unrelenting data growth (that shows no sign of slowing down), tape’s favourable economics, and the prevalent data storage mindset of “save everything, forever,” emanating from regulatory, compliance or governance requirements, and the desire for data to be repurposed and monetized in the future.’
The radical possibilities of data-based profit-making abound in the ‘buzz’ that surrounds big data, an ambitious form of data analytics that has been embraced by academic research councils, security forces and multi-national companies alike.
Presented by proponents as the way to gain insights into consumer behaviour, big data apparently enables companies to unlock the potential of ‘data-driven decision making.’ For example, an article in Computer Weeklydescribes how Ebay is using big data analytics so they can better understand the ‘customer journey’ through their website.
Ebay’s initial forays into analysing big data were in fact relatively small: in 2002 the company kept around 1% of customer data and discarded the rest. In 2007 the company changed their policy, and worked with an established company to develop a custom data warehouse which can now run ad-hoc queries in just 32 seconds.
It is not just Ebay who are storing massive amounts of customer data. According to the BBC, ‘Facebook has begun installation of 10,000 Blu-ray discs in a prototype storage cabinet as back-ups for users’ photos and videos’. While for many years the internet was assumed to be a virtual, almost disembodied space, the desire from companies to monetise information assets mean that the incidental archives created through years of internet searches, have all this time been stored, backed up and analysed.
Amid all the excitement and promotion of big data, the lack of critical voices raising concern about social control, surveillance and ethics is surprising. Are people happy that the data we create is stored, analysed and re-sold, often without our knowledge or permission? What about civil liberties and democracy? What power do we have to resist this subjugation to the irrepressible will of the data-driven market?
‘A recent report from the market intelligence firm IDC estimates that in 2009 stored information totalled 0.8 zetabytes, the equivalent of 800 billion gigabytes. IDC predicts that by 2020, 35 zetabytes of information will be stored globally. Much of that will be customer information. As the store of data grows, the analytics available to draw inferences from it will only become more sophisticated.‘
The development of SONY’s 185 TB tape indicate they are well placed to capitalise on these emerging markets.
The kinds of data stored on the tapes when they become available for professional markets (these tapes are not aimed at consumers) will really depend on the legal regulations placed on companies doing the data collecting. As the case of eBay discussed earlier makes clear, companies will collect all the information if they are allowed to. But should they be? As citizens in the internet society how can ensure we have a ‘right to be forgotten’? How are the shackles of data-driven control societies broken?
Is this the end of tape as we know it? Maybe not quite yet, but October 1, 2014, will be a watershed moment in professional media production in the UK: it is the date that file format delivery will finally ‘go tape-less.’
Establishing end-to-end digital production will cut out what is now seen as the cumbersome use of video tape in file delivery. Using tape essentially adds a layer of media activity to a process that is predominantly file based anyway. As Mark Harrison, Chair of the Digital Production Partnership (DPP), reflects:
Example of a workflow for the DPP AS-11 standard
‘Producers are already shooting their programmes on tapeless cameras, and shaping them in tapeless post production environments. But then a strange thing happens. At the moment a programme is finished it is transferred from computer file to videotape for delivery to the broadcaster. When the broadcaster receives the tape they pass it to their playout provider, who transfers the tape back into a file for distribution to the audience.’
Founded in 2010, the DPP are a ‘not-for-profit partnership funded and led by the BBC, ITV and Channel 4 with representation from Sky, Channel 5, S4/C, UKTV and BT Sport.’ The purpose of the coalition is to help ‘speed the transition to fully digital production and distribution in UK television’ by establishing technical and metadata standards across the industry.
The transition to a standardised, tape-less environment has further been rationalised as a way to minimise confusion among media producers and help economise costs for the industry. As reported on Avid Blogs production companies, who often have to respond to rapidly evolving technological environments, are frantically preparing for deadline day. ‘It’s the biggest challenge since the switch to HD’, said Andy Briers, from Crow TV. Moreover, this challenge is as much financial as it is technical: ‘leading post houses predict that the costs of implementing AS-11 delivery will probably be more than the cost of HDCAM SR tape, the current standard delivery format’, writes David Wood on televisual.com.
Outlining the standard
Audio post production should now be mixed to the EBU R128 loudness standard. As stated in the DPP’s producer’s guide, this new audio standard ‘attempts to model the way our brains perceive sound: our perception is influenced by frequency and duration of sound’ (9).
In addition, the following specifications must be observed to ensure the delivery format is ‘technically legal.’
HD 1920×1080 in an aspect ratio of 16:9 (1080i/25)
Photo Sensitive Epilepsy (flashing) testing to OFCOM standard/ the Harding Test
The shift to file-based delivery will require new kinds of vigilance and attention to detail in order to manage the specific problems that will potentially arise. The DPP producer’s guide states: ‘unlike the tape world (where there may be only one copy of the tape) a file can be copied, resulting in more than one essence of that file residing on a number of servers within a playout facility, so it is even more crucial in file-based workflows that any redelivered file changes version or number’.
Another big development within the standard is the important role performed by metadata, both structural (inherent to the file) and descriptive (added during the course of making the programme) . While broadcasters may be used to manually writing metadata as descriptive information on tape-boxes, they must now be added to the digital file itself. Furthermore, ‘the descriptive and technical metadata will be wrapped with the video and audio into a new and final AS-11 DPP MXF file,’ and if ‘any changes to the file are [made it is] likely to invalidate the metadata and cause the file to be rejected. If any metadata needs to be altered this will involve re-wrapping the file.’
Interoperability: the promise of digital technologies
The sector-wide agreement and implementation of digital file-delivery standards are significant because they represent a commitment to manufacturing full interoperability, an inherent potential of digital technologies. As French philosopher of technology Bernard Stiegler explains:
‘The digital is above all a process of generalised formalisation. This process, which resides in the protocols that enable interoperability, makes a range of diverse and varied techniques. This is a process of unification through binary code of norms and procedures that today allow the formalisation of almost everything: traveling in my car with a GPS system, I am connected through a digitised triangulation process that formalises my relationship with the maps through which I navigate and that transform my relationship with territory. My relationships with space, mobility and my vehicle are totally transformed. My inter-individual, social, familial, scholarly, national, commercial and scientific relationships are all literally unsettled by the technologies of social engineering. It is at once money and many other things – in particular all scientific practices and the diverse forms of public life.’
This systemic homogenisation described by Stiegler is called into question if we consider whether the promise of interoperability – understood here as different technical systems operating efficiently together – has ever been fully realised by the current generation of digital technologies. If this was the case then initiatives like the DPP’s would never have to be pursued in the first place – all kinds of technical operations would run in a smooth, synchronous matter. Amid the generalised formalisation there are many micro-glitches and incompatibilities that slow operations down at best, and grind them to a halt at worst.
With this in mind we should note that standards established by the DPP are not fully interoperable internationally. While the DPP’s technical and metadata standards were developed in close alliance with the US-based Advanced Media Workflow Association’s (AMWA) recently released AS-11 specification, there are also key differences.
As reported in 2012 by Broadcast Now Kevin Burrows, DPP Technical Standards Lead, said: ‘[The DPP standards] have a shim that can constrain some parameters for different uses; we don’t support Dolby E in the UK, although the [AMWA] standard allows it. Another difference is the format – 720 is not something we’d want as we’re standardising on 1080i. US timecode is different, and audio tracks are referenced as an EBU standard.’ Like NTSC and PAL video/ DVD then, the technical standards in the UK differ from those used in the US. We arguably need, therefore, to think about the interoperability of particular technical localities rather than make claims about the generalised formalisation of all technical systems. Dis-synchrony and technical differences remain despite standardisation.
The AmberFin Academy blog have also explored what they describe as the ‘interoperability dilemma’. They suggest that the DPP’s careful planning mean their standards are likely to function in an efficient manner: ‘By tightly constraining the wrapper, video codecs, audio codecs and metadata schema, the DPP Technical Standards Group has created a format that has a much smaller test matrix and therefore a better chance of success. Everything in the DPP File Delivery Specification references a well defined, open standard and therefore, in theory, conformance to those standards and specification should equate to complete interoperability between vendors, systems and facilities.’ They do however offer these words of caution about user interpretation: ‘despite the best efforts of the people who actually write the standards and specifications, there are areas that are, and will always be, open to some interpretation by those implementing the standards, and it is unlikely that any two implementations will be exactly the same. This may lead to interoperability issues.’
It is clear that there is no one simple answer to the dilemma of interoperability and its implementation. Establishing a legal commitment, and a firm deadline date for the transition, is however a strong message that there is no turning back. Establishing the standard may also lead to a certain amount of technological stability, comparable to the development of the EIAJ video tape standards in 1969, the first standardised format for industrial/non-broadcast video tape recording. Amid these changes in professional broadcast standards, the increasingly loud call for standardisation among digital preservationists should also be acknowledged.
For analogue and digital tapes however, it may well signal the beginning of an accelerated end. The professional broadcast transition to ‘full-digital’ is a clear indication of tape’s obsolescence and vulnerability as an operable media format.
If you work in digital preservation then the term ‘significant properties’ will no doubt be familiar to you. The concept has been viewed as a hindrance due to being shrouded by foggy terminology, as well as a distinct impossibility because of the diversity of digital objects in the world which, like their analogue counterparts, cannot be universally generalised or reduced to a series of measurable characteristics.
In a technical sense, establishing a set of core characteristics for file formats has been important for initiatives like Archivematica, ‘a free and open-source digital preservation system that is designed to maintain standards-based, long-term access to collections of digital objects.’ Archivematica implement ‘default format policies based on an analysis of the significant characteristics of file formats.’ These systems manage digital information using an ‘agile software development methodology’ which ‘is focused on rapid, iterative release cycles, each of which improves upon the system’s architecture, requirements, tools, documentation, and development resources.’
Such a philosophy may elicit groans of frustration from information managers who may well want to leave their digital collections alone, and practice a culture of non-intervention. Yet this adaptive-style of project management, which is designed to respond rapidly to change, is often contrasted with predictive development that focuses on risk assessment and the planning of long-term projects. The argument against predictive methodologies is that, as a management model, it can be unwieldy and unresponsive to change. This can have damaging financial consequences, particularly when investing in expensive, risky and large scale digital preservation projects, as the BBC’s failed DMI initiative demonstrates.
Indeed, agile software development methodology may well be an important key to the sustainability of digital preservation systems which need to find practical ways of maneuvering technological innovations and the culture of perpetual upgrade. Agility in this context is synonymous with resilience, and the practical application of significant properties as a means to align file format interoperability offers a welcome anchor for a technological environment structured by persistent change.
Significant properties vs the authentic digital object
What significant properties imply, as archival concept and practice, is that desiring authenticity for the digitised and born-digital objects we create is likely to end in frustration. Simply put, preserving all the information that makes up a digital object is a hugely complex affair, and is a procedure that will require numerous and context-specific technical infrastructures.
As Trevor Owens explains: ‘you can’t just “preserve it” because the essence of what matters about “it” is something that is contextually dependent on the way of being and seeing in the world that you have decided to privilege.’ Owens uses the example of the Geocites web archiving project to demonstrate that if you don’t have the correct, let’s say ‘authentic’ tools to interpret a digital object (in this case, a website that is only discernible on certain browsers), you simply cannot see the information accurately. Part of the signal is always missing, even if something ‘significant’ remains (the text or parts of the graphics).
It may be desirable ‘to preserve all aspects of the platform in order to get at the historicity of the media practice’, Jonathan Sterne, author of MP3: Meaning of a Format suggests, but in a world that constantly displaces old technological knowledge with new, settling for the preservation of significant properties may be a pragmatic rather than ideal solution.
Analogue to digital issues
To bring these issues back to the tape we work we with at Great Bear, there are of course times when it is important to use the appropriate hardware to play the tapes back, and there is a certain amount of historically specific technical knowledge required to make the machines work in the first place. We often wonder what will happen to the specialised knowledge learnt by media engineers in the 70s, 80s and 90s, who operated tape machines that are now obsolete. There is the risk that when those people die, the knowledge will die with them. Of course it is possible to get hold of operating manuals, but this is by no means a guarantee that the mechanical techniques will be understood within a historical context that is increasingly tape-less and software-based. By keeping our wide selection of audio and video tape machines purring, we are sustaining a machinic-industrial folk knowledge which ultimately helps to keep our customer’s magnetic tape-based, media memories, alive.
Of course a certain degree of historical accuracy is required in the transfers because, very obviously, you can’t play a V2000 tape on a VHS machine, no matter how hard you try!
Yet the need to play back tapes on exactly the same machine becomes less important in instances where the original tape was recorded on a domestic reel-to-reel recorder, such as the Grundig TK series, which may not have been of the greatest quality in the first place. To get the best digital transfer it is desirable to play back tapes on a machine with higher specifications that can read the magnetic information on the tape as fully as possible. This is because you don’t want to add any more errors to the tape in the transfer process by playing it back on a lower quality machine, which would then of course become part of the digitised signal.
It is actually very difficult to remove things like wow and flutterafter a tape has been digitised, so it is far better to ensure machines are calibrated appropriately before the tape is migrated, even if the tape was not originally recorded on a machine with professional specifications. What is ultimately at stake in transferring analogue tape to digital formats is the quality of the signal. Absolute authenticity is incidental here, particularly if things sound bad.
The moral of this story, if there can be one, is that with any act of transmission, the recorded signal is liable to change. These can be slight alterations or huge drop-outs and everything in-between. The agile software developers know that given the technological conditions in which current knowledge is produced and preserved, transformation is inevitable and must be responded to. Perhaps it is realistic to assume this is the norm in society today, and creating digital preservation systems that are adaptive is key to the survival of information, as well as accepting that preserving the ‘full picture’ cannot always be guaranteed.
We are currently migrating a collection of tapes made by Irene Brown who, in the late 1960s, was a school teacher living in Inverness. Irene was a member of the Inverness Folk Club and had a strong interest in singing, playing guitar and collecting the musical heritage of folk and Gaelic culture.
The tapes, that were sent by her niece Mrs. Linda Baublys, are documents of her Auntie’s passion, and include recordings Irene made of folk music sung in a mixture of Gaelic and English at the Gellions pub, Inverness, in the late 1960s.
The tapes also include recordings of her family singing together. Linda remembered fondly childhood visits to her ‘Granny’s house that was always filled with music,’ and how her Auntie used to ‘roar and sing.’
Perhaps most illustriously, the tapes include a prize-winning performance at the annual An Comunn Gaidhealach/ The National Mòd (now Royal National Mòd). The festival, which has taken place annually at different sites across Scotland since it was founded in 1892 is modelled on the Welsh Eisteddfod and acts ‘as a vehicle for the preservation and development of the Gaelic language. It actively encourages the teaching, learning and use of the Gaelic language and the study and cultivation of Gaelic literature, history, music and art.’ Mòd festivals also help to keep Gaelic culture alive among diasporic Scottish communities, as demonstrated by the US Mòd that has taken place annually since 2008.
If you want to find out more about Gaelic music visit the Year of the Song website run by BBC Alba where you can access a selection of songs from the BBC’s Gaelic archive. If you prefer doing research in archives and libraries take a visit to the School of Scottish Studies Archives. Based at the University of Edinburgh, the collection comprises a significant sound archive containing thousands of recordings of songs, instrumental music, tales, verse, customs, beliefs, place-names biographical information and local history, encompassing a range of dialects and accents in Gaelic, Scots and English.
As well as learning some of the songs recorded on the tape to play herself, Linda plans to eventually deposit the digitised transfers with the School of Scottish Studies Archives. She will also pass the recordings on to a local school that has a strong engagement with traditional Gaelic music.
Digitising and country lanes
Linda told us it was a ‘long slog’ to get the tapes. After Irene died at the age of 42 it was too upsetting for her mother, and Linda’s Granny, to listen to them. The tapes were then passed onto Linda’s mother who also never played the tapes, so when she passed away Linda, who had been asking for the tapes for nearly 20 years, took responsibility to get them digitised.
The tapes were in fairly good condition and minimal problems arose in the transfer process. One of the tapes was however suffering from ‘country-laning’. This is when the shape of the tape has become bendy (like a country lane), most probably because it had been stored in fluctuating temperatures which cause the tape to shrink and grow. It is more common in acetate-backed tape, although Linda’s tapes were polymer-backed. Playing a tape suffering from country-laning often results in problems with the azimuth because the angle between tape head and tape are dis-aligned. A signal can still be discerned, because analogue recordings rarely drop out entirely (unlike digital tape), but the recording may waver or otherwise be less audible. When the tape has been deformed in this way it is very difficult to totally reverse the process. Consequently there has to be some compromise in the quality of the transfer.
We hope you will enjoy this excerpt from the tapes, which Linda has kindly given us permission to include in this article.
The Women’s Liberation Movement (WLM) is full of quirky examples of how womyn tried to wrestle culture from the sordid grip of male domination.
Part of this process was reinventing the world in wimmin’s image, word and song; to create and reclaim a lasting herstory in which sisterhood could flourish.
A recent U-Matic video tape transferconducted in the Greatbear studio offers a window into this cultural heritage.
State Your Destination was a film made by Bristol-based ’80s feminist film collective Women in Moving Pictures (W.I.M.P.S.), whose complete archive is stored at the Feminist Archive South.
The way women shirked the language of patriarchy is evident on the tape box. We digitised the ‘MISTRESS’ copy, not the master copy.
Seeing the mistress copy today is a reminder of the way gendered language influences how we can think about cultural forms. The master copy, of course, in conventional understanding, is the finished article, the final cut. The master of the house – the person in charge – is gendered male. Yet is this still the case?
‘If we find that audio-technical discourse renders signal processing in terms of masculinist languages of mastery and domination of nature, can we help but wonder after its broader social implications? Does it not also suggest a gendered set of relations to these technologies? It is any wonder we still find the design, implementation, marketing, and use of audio-signal processing technologies to be male-dominated fields? [To change things] it will require fundamentally rethinking how we model, describe, interact, and sound with signal processing technologies’.
For feminist women who felt systematically excluded from certain kinds of cultural and economic activity, the gendering of language was an extension of violence they experienced because they were women.
Making the tape a MISTRESS may help rectify the problem, as does crossing out the very idea of a master copy.
The magnetic viewer makes the mysterious tracks recorded onto the tape visible
We use a Sigma Hi-Chemical MV-95 magnetic viewer in order to aid our digitisation work. By pressing the viewer against the tape we are able to read the magnetic information recorded on it. The reader helps us to visually identify the position of the recorded tracks on the tape, and enables accurate playback during digitisation. Magnetic readers can also help us to identify potential problems with the tape, for example if a track has been partially erased, because it will show up on the viewer.
We receive tapes that are in varying states of repair and disrepair. Sometimes the person who made the recording kept the tapes in impeccable, temperature controlled conditions. Inscribed on the boxes are dates and lists of who performed, and what instrument they played. The tapes often feature detailed notes about the number of tracks recorded, whether they are in stereo or mono and if they used noise reduction technology. Digitisation, in such cases, does not usually pose great challenges.
At the other extreme are tapes recorded by people who never wrote anything down about how they made their recording. This means the people doing the digitising can be left to do a lot of guess work (particularly if that person has since died, and can’t tell you anything about the recording). A lack of informative metadata about the tape does not necessarily create migration difficulties: recordings can be very straightforward like, for example, a ½ track stereo recording of a single voice.
It is essential that the appropriate head is used to read the magnetic information recorded onto the tape.
Problems can however arise when recordings have been made in an idiosyncratic (and inconsistent) manner. For example (and in exceptional circumstances) we receive single magnetic tapes that have a mixture of track formats on them which include four track multi-track, ½ and ¼ track mono and ½ and ¼ track stereo.
In such cases it can be hard to discern the precise nature of the recordings using the ears alone. Often such recordings don’t sound ‘quite right’, even if it is not exactly clear what the problem is.
Rather than relying on speculation, using the magnetic reader gives 100% confirmation about where tracks are recorded on the tape, and therefore helps us to replay the tape using the appropriate playback heads, and therefore digitise it accurately.
If you are new to the world of digital preservation, you may be feeling overwhelmed by the multitude of technical terms and professional practices to contend with, and the fact that standards never seem to stay in place for very long.
Fortunately, there are many resources related to digital preservation available on the internet. Unfortunately, the large amount of websites, hyperlinks and sub-sections can exacerbate those confounded feelings.
In order to help the novice, nerd or perplexed archivist wanting to learn more, we thought it would be useful to compile a selection of (by no means exhaustive) resources to guide your hand. Ultimately if content is to be useful it does need to be curated and organised.
Bear in mind that individual websites within the field tend to be incredibly detailed, so it is worth having a really good explore to find the information you need! And, as is the norm with the internet, one click leads to another so before you know it you stumble upon another interesting site. Please feel free to add anything you find to the comment box below so the list can grow!
Digital Preservation
AV Preserve are a US-based consultation company who work in partnership with organisations to help them implement digital information preservation and dissemination plans. They have an amazing ‘papers and presentation’ section of their website, which includes research about diverse areas such as assessing cloud storage, digital preservation software, metadata, making an institutional case for digital preservation, managing personal archives, primers on moving image codecs, disaster recovery and many more. It is a treasure trove, and there is a regularly updated blog to boot!
The Digital Preservation Coalition‘s website is full of excellent resources including a digital preservation jargon buster, case studies, preservation handbook and a ‘what’s new’ section. The Technology Watch Reports are particularly useful. Of relevance to the work Great Bear do is the ‘Preserving Moving Pictures and Sound’, but there are many others including Intellectual Property and Copyright, Preserving Metadata and Digital Forensics.
Preservation Guide Wiki – Set up initially by Richard Wright, BBC as early as 2006, the wiki provides advice on getting started in audiovisual digital preservation, developing a strategy at institutional and project based levels.
The PrestoCentre’s website is amazing resource to explore if you want to learn more about digital preservation. The organisation aim to ‘enhance the audiovisual sector’s ability to provide long-term access to cultural heritage’. They have a very well stocked library that is composed of tools, case studies and resources, as well as a regularly updated blog.
The European Archival Records and Knowledge Preservation (E-Ark) project promises to collect important research about the sustainability of digital archives across Europe. The website is currently being developed so don’t expect much from it, but it is good to know this research is happening.
The A/V Artifact Atlas is a community-generated resource for people working in digital preservation and aims to identify problems that occur when migrating tape-based media. The Atlas is made in a wiki-format and welcomes contributions from people with expertise in this area – ‘the goal is to collectively build a comprehensive resource that identifies and documents AV artifacts.’ The Atlas was created by people connected to the Bay Area Video Coalition, a media organisation that aims to inspire ‘social change by empowering media makers to develop and share diverse stories through art, education and technology.’
Richard Hess is a US-based audio restoration expert. Although his website looks fairly clunky, he is very knowledgeable and well-respected in the field, and you can find all kinds of esoteric tape wisdom on there.
The National Technology Alliance’s Magnetic Tape Storage and Handling: A Guide for Libraries and Archives by Dr. John W.C. Van Bogart (1995) is an excellent resource, written in non-technical language and explores the kinds of things that can go wrong with magnetic tape (and how to avoid it!)
The National Film and Sound Archive of Australia have produced an in-depth online Preservation Guide. It includes a film preservation handbook, an audiovisual glossary, advice on caring for your collection and disaster management.
The British Library’s Playback and Recording Equipment directory is well worth looking through. Organised chronologically (from 1877 – 1990s), by type and by model, it includes photos, detailed descriptions and you can even view the full metadata for the item. So if you ever wanted to look at a Columbia Gramophone from 1901 or a SONY O-matic tape recorder from 1964, here is your chance!
Digital Heritage
In 2005 UNESCO declared 27 October to be World Audiovisual Heritage Day. The web pages are an insight into the way audiovisual heritage is perceived by large, international policy bodies.
The Digital Curation Centre works to support Higher Education Institutions to interpret and manage research data. Again, this website is incredibly detailed, presenting case studies, ‘how-to’ guides, advice on digital curation standards, policy, curation lifecycle and much more.
Europeana is a multi-lingual online collection of millions of digitized items from European museums, libraries, archives and multi-media collections.
Digital Preservation Tools and Software
For open source digital preservation software check out The Open Planets Foundation (OPF), who address core digital preservation challenges by engaging with its members and the community to develop practical and sustainable tools and services to ensure long-term access to digital content. The website also includes the very interesting Atlas of Digital Damages
Archivematica is a free and open-source digital preservation system that is designed to maintain standards-based, long-term access to collections of digital objects.
The BBC’s R & D Archive is an invaluable resource of white papers, research and policy relating to broadcast technology from the 1930s onwards. As the website states, ‘whether it’s noise-cancelling microphones in the 1930s, the first transatlantic television transmission in the 1950s, Ceefax in the 1970s, digital radio in the 1990s and HD TV in the 2000s, or the challenge to “broadcasting” brought about by the internet and interactive media, BBC Research & Development has led the way with innovative technology and collaborative ways of working.’
As mentioned above, please feel free to add your website or project to the comment box below. We will continue to update this list!
The summer of 2008 saw a spate of articles in the media focusing on a new threat to magnetic tapes.
The reason: the warm, wet weather was reported as a watershed moment in magnetic tape degradation, with climate change responsible for the march of mould consuming archival memories, from personal to institutional collections.
The connection between climate change and tape mould is not one made frequently by commentators, even in the digital preservation world, so what are the links? It is certainly true that increased heat and moisture are prime conditions for the germination of the mould spores that populate the air we breathe. These spores, the British Library tell us
‘can stay dormant for long periods of time, but when the conditions are right they will germinate. The necessary conditions for germination are generally:
• temperatures of 10-35ºC with optima of 20ºC and above
• relative humidities greater than 70%’
The biggest threat to the integrity of magnetic tape is fluctuations in environmental temperatures. This means that tape collections that are not stored in controlled settings, such as a loft, cupboard, shed or basement, are probably most at risk.
While climate change has not always been taking as seriously as it should be by governments and media commentators, the release today of the UN’s report, which stated in no uncertain terms that climate change is ‘severe, pervasive and irreversible’, should be a wake up call to all the disbelievers.
To explore the links between climate change and tape degradation further we asked Peter Specs from US-based disaster recovery specialists the Specs Brothers if he had noticed any increase in the number of mouldy tapes they had received for restoration. In his very generous reply he told us:
‘The volume of mouldy tapes treated seems about the same as before from areas that have not experienced disasters but has significantly increased from disaster areas. The reason for the increase in mould infected tapes from disaster areas seems to be three-fold. First, many areas have recently been experiencing severe weather that is not usual for the area and are not prepared to deal with the consequences. Second, a number of recent disasters have affected large areas and this delays remedial action. Third, after a number of disasters, monies for recovery seem to have been significantly delayed. We do a large amount of disaster recovery work and, when we get the tapes in for processing fairly quickly, are generally able to restore tapes from floods before mould can develop. In recent times, however, we are getting more and more mouldy tapes in because individuals delayed having them treated before mould could develop. Some were unaware that lower levels of their buildings had suffered water damage. In other areas the damage was so severe that the necessities of life totally eclipsed any consideration of trying to recover “non-essential” items such as tape recordings. Finally, in many instances, money for recovery was unavailable and individuals/companies were unwilling to commit to recovery costs without knowing if or when the government or insurance money would arrive.’
Nigel Bewley, soon to be retired senior sound engineer at the British Library, also told us there had been no significant increase in the number of mouldy tapes they had received for treatment. Yet reading between the lines here, and thinking about what Pete Specs told us, in an age of austerity and increased natural disasters, restoring tape collections may slip down the priority list of what needs to be saved for many people and institutions.
Mould: Prevention Trumps the Cure
Climate change aside, what can be done to prevent your tape collections from becoming mouldy? Keeping the tapes stored in a temperature controlled environment is very important – ’15 + 3° C and 40% maximum relative humidity (RH) are safe practical storage conditions,’ recommend the National Technology Alliance. It is also crucial that storage environments retain a stable temperature, because significant changes in the storage climate risk heating or cooling the tape pack, making the tension in the tape pack increase or decrease which is not good for the tape.
Because mould spores settle in very still air, it is vital to ensure a constant flow of air and prevent moist conditions. If all this is too late and your tape collections are already mouldy, all is not lost – even the most infected tape can be treated carefully and salvaged and we can help you do this.
If you are wondering how mould attacks magnetic tape, it is attracted to the binder or adhesive that attaches the layers of the tape together. If you can see the mould on the tape edges it usually means the mould has infected the whole tape.
Optical media can also be affected by mould. Miriam B. Kahn writes in Disaster Response and Planning for Libraries
‘Optical discs are susceptible to water, mould and mildew. If the polycarbonate surface is damaged or not sealed appropriately, moisture can become trapped and begin to corrode the metal encoding surface. If moisture or mould is invasive enough, it will make the disc unreadable’ (85).
Prevention, it seems, is better than having to find the cure. So turn on the lights, keep the air flowing and make the RH level stable.
The history of amateur recording is peppered with examples of people who stretched technologies to their creative limit. Whether this comes in the form of hours spent trying things out and learning through doing, endlessly bouncing tracks in order to turn an 8-track recording into a 24-track epic or making high quality audio masters on video tape, people have found ways to adapt and experiment using the tools available to them.
One of the lesser known histories of amateur home recordings is making high quality stereo mixdowns and master recordings from multi-track audio tape onto consumer-level Hi-Fi VCRs.
We are currently migrating a stereo master VHS Hi-Fi recording of London-based indie band Hollow Hand. Hollow Hand later adopted the name Slanted and were active in London between 1992-1995. The tapes were sent in by Mark Venn, the bass player with Slanted and engineer for these early recordings that were recorded in 1992 in the basement of a Clapham squat. Along with the Hi-Fi VHS masters, we have also been sent eight reels of AMPEX ¼ tapes of Slanted that are being transferred for archival purposes. Mark intends to remix the eight track recordings digitally but as of yet has no plans for a re-release.
When Mark sent us the tapes to be digitised he thought they had been encoded with a SONY PCM, a mixed digital/ analogue recording method we have covered in a previous blog post. The tapes had, however, been recorded directly from the FOSTEX eight track recorder to the stereo Hi-Fi function on a VHS video tape machine. For Mark at the time this was the best way to get a high quality studio master because other analogue and digital tape options, such as Studer open reel to reel and DAT machines, were financially off-limits to him. It is worth mentioning that Hi-Fi audio technologies were introduced in the VHS model by JVC around 1984, so using this method to record stereo masters would have been fairly rare, even among people who did a lot of home recording. It was certainly a bit of a novelty in the Great Bear Studio – they are the first tapes we have ever received that have been recorded in this way – and take it for granted that we see a lot of tape.
Using the Hi-Fi function on VHS tape machines was probably as good as it got in terms of audio fidelity for those working in an exclusively analogue context. It produced a master recording comparable in quality to a CD, particularly if the machine had manual audio recording level control. This is because, as we wrote about in relation to PCM/ Betamax, video tape could accommodate greater bandwidth that audio tape (particularly audio cassette), therefore leading to better quality recordings.
One of our replacement upper head drums
VHS Hi-Fi audio is achieved using audio frequency-modulation (AFM) and relied on a form of magnetic recording called ‘depth multiplexing‘. This is when
‘the modulated audio carrier pair was placed in the hitherto-unused frequency range between the luminance and the colour carrier (below 1.6 MHz), and recorded first. Subsequently, the video head erases and re-records the video signal (combined luminance and colour signal) over the same tape surface, but the video signal’s higher centre frequency results in a shallower magnetization of the tape, allowing both the video and residual AFM audio signal to coexist on tape.’
Challenges for migrating Hi-Fi VHS Audio
Although the recordings of Hollow Hand are in good working condition, analogue masters to VHS Hi-Fi audio do face particular challenges in the migration process.
Playing back the tapes in principle is easy if both tape and machine are in optimum condition, but if either are damaged the original recordings can be hard to reproduce.
A particular problem for Hi-Fi audio emerges when the tape heads wear and it becomes harder to track the hi-fi audio recording because the radio frequency signal (RF) can’t be read consistently off the tape. Hi-Fi recordings are harder to track because of depth multiplexing, namely the position of the recorded audio relative to the video signal. Even though there is no video signal as such in the playback of Hi-Fi audio, the video signal is still there, layered on top of the audio signal, essentially making it harder to access. Of course when tape heads/ drums wear down they can always be replaced, but acquiring spare parts will become increasingly difficult in years to come, making Hi-Fi audio recordings on VHS particularly threatened.
In order to migrate tape-based media to digital files in the most effective way possible, it is important to use appropriate machines for the transfer. The Panasonic AG-7650 we used to transfer the Hollow Hand tapes afforded us great flexibility because it is possible to select which audio tracks are played back at any given time which meant we could isolate the Hi-Fi audio track. The Panasonic AG-7650 also has tracking meters which makes it easy to assess and adjust the tracking of the tape and tape head where necessary.
As ever, the world of digitisation continues to generate anomalies, surprises and good stories. Who knows how many other video/ audio hybrid tapes are out there! If you do possess an archive collection of such tapes we advise you to take action to ensure they are migrated because of the unique problems they pose as a storage medium.
Whole subcultures have emerged in this memory boom, as digital technologies enable people to come together via a shared passion for saving obscurities presumed to be lost forever. One such organisation is Kaleidoscope, whose aim is to keep the memory of ‘vintage’ British television alive. Their activities capture an urgent desire bubbling underneath the surface of culture to save everything, even if the quality of that everything is questionable.
Of course, as the saying goes, one person’s rubbish is another person’s treasure. As with most cultural heritage practices, the question of value is at the centre of people’s motivations, even if that value is expressed through a love for Pan’s People, Upstairs, Downstairs, Dick Emery and the Black and White Minstrel Show.
We were recently contacted by a customer hunting for lost TV episodes. His request: to lay hands on any old tapes that may unwittingly be laden with lost jewels of TV history. His enquiry is not so strange since a 70s Top of the Pops programme, a large proportion of which were deleted from the official BBC archive, trailed the end of ½ EIAJ video tape we recently migrated. And how many other video tapes stored in attics, sheds or barns potentially contain similar material? Or, as stated on the Kaleidoscope website:
‘Who’d have ever imagined that a modest, sometimes mould-infested collection of VHS tapes in a cramped back bedroom in Pill would lead to the current Kaleidoscope archive, which hosts the collections of many industry bodies as well as such legendary figures as Bob Monkhouse or Frankie Howard?’
Selection and appraisal in the archive
Mysterious tapes?
Living in an age of seemingly infinite information, it is easy to forget that any archival project involves keeping some things and throwing away others. Careful considerations about the value of an item needs to be made, both in relation to contemporary culture and the projected needs of subsequent generations.
These decisions are not easy and carry great responsibility. After all, how is it possible to know what society will want to remember in 10, 20 or even 30 years from now, let alone 200? The need to remember is not static either, and may change radically over time. What is kept now also strongly shapes future societies because our identities, lives and knowledge are woven from the memory resources we have access to. Who then would be an archivist?
When faced with a such a conundrum the impulse to save everything is fairly seductive, but this is simply not possible. Perhaps things were easier in the analogue era when physical storage constraints conditioned the arrangement of the archive. Things had to be thrown away because the clutter was overwhelming. With the digital archive, always storing more seems possible because data appears to take up less space. Yet as we have written about before on the blog, just because you can’t touch or even see digital information, doesn’t mean it is not there. Energy consumption is costly in a different way, and still needs to be accounted for when appraising how resource intensive digital archives are.
For those who want their media memories to remain intact, whole and accessible, learning about the clinical nature of archival decisions may raise concern. The line does however need to be drawn somewhere. In an interview in 2004 posted on the Digital Curation Centre’s website, Richard Wright, who worked in the BBC’s Information and Archives section, explained the long term preservation strategy for the institution at the time.
‘For the BBC, national programmes that have entered the main archive and been fully catalogued have not, in general, been deleted. The deletions within the retention policy mainly apply to “contribution material” i.e. components (rushes) of a final programme, or untransmitted material. Hence, “long-term” for “national programmes that have entered the main archive and been fully catalogued” means in perpetuity. We have already kept some material for more than 75 years, including multiple format migrations.’
Value – whose responsibility?
For all those episodes, missing believed wiped, the treasure hunters who track them down tread a fine line between a personal obsession and offering an invaluable service to society. You decide.
What is inspiring about amateur preservationists is that they take the question of archival value into their own hands. In the 21st century, appraising and selecting the value of cultural artifacts is therefore no longer the exclusive domain of the archivist, even if expertise about how to manage, describe and preserve collections certainly is.
Does the popularity of such activities change the constitution of archives? Are they now more egalitarian spaces that different kinds of people contribute to? It certainly suggests that now, more than ever, archives always need to be thought of in plural terms, as do the different elaborations of value they represent.
We are pleased to announce that we are now able to support the transfer of 2″ Quadruplex Video Tape (PAL, SECAM & NTSC) to digital formats.
2” Quad was a popular broadcast analogue video tape format whose halcyon period ran from the late 1950s to the 1970s. The first quad video tape recorder made by AMPEX in 1956 cost a modest $45,000 (that’s $386,993.38 in today’s money).
2” Quad revolutionized TV broadcasting which previously had been reliant on film-based formats, known in the industry as ‘kinescope‘ recordings. Kinescope film required significant amounts of skilled labour as well as time to develop, and within the USA, which has six different time zones, it was difficult to transport the film in a timely fashion to ensure broadcasts were aired on schedule.
To counter these problems, broadcasters sought to develop magnetic recording methods, that had proved so successful for audio, for use in the television industry.
The first experiments directly adapted the longitudinal recording method used to record analogue audio. This however was not successful because video recordings require more bandwidth than audio. Recording a video signal with stationary tape heads (as they are in the longitudinal method), meant that the tape had to be recorded at a very high speed in order accommodate sufficient bandwidth to reproduce a good quality video image. A lot of tape was used!
Ampex, who at the time owned the trademark marketing name for ‘videotape’, then developed a method where the tape heads moved quickly across the tape, rather than the other way round. On the 2” quad machine, four magnetic record/reproduce heads are mounted on a headwheel spinning transversely (width-wise) across the tape, striking the tape at a 90° angle. The recording method was not without problems because, the Toshiba Science Museum write, it ‘combined the signal segments from these four heads into a single video image’ which meant that ‘some colour distortion arose from the characteristics of the individual heads, and joints were visible between signal segments.’
The limitations of Quadruplex recording influenced the development of the helical scan method, that was invented in Japan by Dr. Kenichi Sawazaki of the Mazda Research Laboratory, Toshiba, in 1954. Helical scanning records each segment of the signal as a diagonal stripe across the tape. ‘By forming a single diagonal, long track on two-inch-wide tape, it was possible to record a video signal on one tape using one head, with no joints’, resulting in a smoother signal. Helical scanning was later widely adopted as a recording method in broadcast and domestic markets due to its simplicity, flexibility, reliability and economical use of tape.
This brief history charting the development of 2″ Quad recording technologies reveals that efficiency and cost-effectiveness, alongside media quality, were key factors driving the innovation of video tape recording in the 1950s.
What is particularly interesting about the consortium E-Ark has brought together is commercial partners will be part of a conversation that aims to establish long term solutions for digital preservation across Europe. More often than not, commercial interests have driven technological innovations used within digital preservation. This has made digital data difficult to manage for institutions both large and small, as the BBC’s Digital Media Initiative demonstrates, because the tools and protocols are always in flux. A lack of policy-level standards and established best practices has meant that the norm within digital information management has very much been permanent change.
Such a situation poses great risks for both digitised and born digital collections because information may have to be regularly migrated in order to remain accessible and ‘open’. As stated on the E-Ark website, ‘the practices developed within the project will reduce the risk of information loss due to unsuitable approaches to keeping and archiving of records. The project will be public facing, providing a fully operational archival service, and access to information for its users.’
The E-Ark project will hopefully contribute to the creation of compatible systems that can respond to the different needs of groups working with digital information. Which is, of course, just about everybody right now: as the world economy becomes increasingly defined by information and ‘big data’, efficient and interoperable access to commercial and non-commercial archives will be an essential part of a vibrant and well functioning economic system. The need to establish data systems that can communicate and co-operate across software borders, as well as geographical ones, will become an economic necessity in years to come.
The task facing E-Ark is huge, but one crucial to implement if digital data is to survive and thrive in this brave new datalogical world of ours. As E-Ark explain: ‘Harmonisation of currently fragmented archival approaches is required to provide the economies of scale necessary for general adoption of end-to-end solutions. There is a critical need for an overarching methodology addressing business and operational issues, and technical solutions for ingest, preservation and re-use.’
Maybe 2014 will be the year when digital preservation standards start to become a reality. As we have already discussed on this blog, the US-based National Agenda for Digital Stewardship 2014 outlined the negative impact of continuous technological change and the need to create dialogue among technology makers and standards agencies. It looks like things are changing and much needed conversations are soon to take place, and we will of course reflect on developments on the Great Bear blog.
Philip Jap came from a time when mime, dance, slapped bass lines, mascara and techno-dystopic anthems were staple parts of a successful popular music career. Cut from the same new wave goth cloth as Gary Numan, Human League and John Foxx, sporting mesmeric dance moves like a male Kate Bush, Jap lit up the early 1980s with performances on the David Essex Showcase, an audience participation talent show similar to today’s Britain’s Got Talent or Pop Idol. Jap went on to sign for Carlin Music Publishing and A&M Records, release an eponymous solo album and have a top 40 hit with ‘Save Us,’ a dramatic plea for liberation from an increasingly intrusive ‘mechanical world.’
Jap retains a modest yet loyal fanbase (The Philip Jap Army), and his recordings will soon be made available through his twitter site. Although he did not have runaway commercial chart success, Jap went on to have a successful career as a composer and arranger for TV series and commercials and is the co-founder of AUDIOfield, a music production company.
The Greatbear studio has been graced with Jap’s music this week because we have been migrating a collection of low-band U-matic videos that feature a number of TV appearances and promotional videos, including the 30 minute ‘special’ that was recorded for the BBC. In similar fashion to our recent transfer of Manchester Oi! band State Victims, the tapes were found in an old suitcase in a barn!
Although the tapes were mostly in good condition, some of the tapes were recorded on early SONY brand and were suffering from low Radio Frequency (RF) levels. RF levels are the recorded levels that can be read off the tape itself. To get a good, clear picture it is essential that the RF levels are strong. According to the AV Artifact Atlas, RF deterioration can occur because of a ‘poorly made recording on broken or mis-calibrated machine/record heads, or the use of poor quality video tape stock.’ Low RF levels may also occur if ‘the source media itself has been exposed to a strong magnetic field (unshielded speakers, motors, high-voltage transformers, etc.)’.
When a tape is suffering from low RF levels there are not loads of things you can do to reverse the process. This is because the signal recorded on the tape has essentially faded over time, due to a bad initial recording, unsuitable storage conditions leading to de-magnetisation or sticky shed, or poor quality tape (such as AMPEX or SONY U-matic tapes, although not exclusively). It is possible however to modify the tracking, a calibration adjustment which ensures the spinning playback head is properly aligned with the helical scan signal written onto the video tape. Tracking changes the speed at which the tape moves past the tape heads, which although spinning during playback, remain stationary. It is not the answer of all low RF ills, however, because the signal on the tape itself has become weaker, even if the calibration adjustment helps the machine read the signal more effectively.
Thankfully the tapes play back well, which is pretty amazing given that the tapes are over 30 years old and were never meant to be archive copies in the first place. We have also had a pretty enjoyable time watching and listening to Philip Jap’s amazing music. It is definitely time for a revival!
