Record Store Day is usually 'the one day each year when over 200 independent record shops all across the UK come together to celebrate their unique culture. Special vinyl releases are made exclusively for the day, in what’s become one of the biggest annual events on the music calendar.' This year, due to COVID-19, Record Store Day is being split across 3 dates: 29th August, 26th September and 24th October.
This Record Store Day, Saturday 29th August 2020, is particularly exciting for Greatbear as it sees the release on Vinyl Revival, Manchester of The High - Martin Hannett Sessions, a restoration and digitisation project we worked on earlier this year.
One of the Martin Hannett session DAT tapes digitised at Greatbear
Martin Hannett - Manchester music producer, known for his era-defining creative work with Buzzcocks, Joy Division, New Order, John Cooper Clarke, The Stone Roses, Happy Mondays and many others - died aged 42 in April 1991.
The tapes we received were DAT (Digital Audio Tape) masters, produced by Hannett at recording sessions with The High in 1989 (at Strawberry Studios) and 1991 (at Great Linford Manor), and included Hannett's last production work before his untimely death.
The High - Martin Hannett session at Strawberry Studios 1989: producer Martin Hannett / Hannett inspecting DAT manual. Stills from footage by Nigel Couzens.
The High - Martin Hannett session at Strawberry Studios 1989: mixing desk / Andy Couzens. Stills from footage by Nigel Couzens.
The High were formed in 1989 by former Turning Blue singer John Matthews and former Buzzcocks F.O.C. members Andy Couzens (guitar, also formerly of The Stone Roses and pre-Roses bands The Patrol and Waterfront), Simon Davies (bass), and drummer Chris Goodwin (also formerly of the Waterfront as well as the Inspiral Carpets). They were signed by London Records and had three UK Singles Chart hits in 1990 before breaking into the top 30 in 1991 with a revamped version of their debut single, the Martin Hannett-produced "Box Set Go".
The High DAT cassette insert card tracks 1-4
The High DAT cassette insert card tracks 5-9
analogue to digital
From the Nigel Couzens footage (see video clip below), it looks like the Strawberry Studios sessions were recorded to 2 inch analogue tape, on a 24 track Studer A80. This was quite an old machine at that time as there would have been the A800 and possibly the A820 available too - but maybe they just loved the sound on the A80.
DAT, introduced by Sony in 1987, became popular in the audio and recording industry for mastering during the 1990s. The initial recordings would be made to 2" (or other width) analogue tape, but the mixed and produced final versions would be recorded to DAT - allowing the benefits of lossless encoding and avoiding the addition of further analogue tape hiss at the mastering stage. This process could be seen as a stepping stone towards an emerging all-digital production chain, and the development of hard disk recording.
fragile tape
At 3.81mm wide and 0.013mm thick, DAT is more fragile than other cassette-based digital tape formats such as DTRS/DA-88, ADAT and PCM digital audio, or any of the reel-to-reel formats (analogue or digital).
This makes it vulnerable to ripping. The High - Martin Hannett Sessions DAT masters arrived at Greatbear with visible signs of mould growth along the edges of the tape. (See the fuzzy white threads along the surface of the tape pack in the pictures above and below.) When this happens, the mould sticks the layers of the tape together - particularly along the edges - which inevitably leads to the tape ripping under the high tension of playback.
A ripped tape is especially problematic because DAT uses a helical scan recording system, based on a miniature video transport, and so cannot be spliced for clean edits. (Splices also risk irreparable damage to heads on the drum of the playback machine.) A ripped DAT tape - the helically-imprinted signal being bisected - results in irreversible signal loss.
Red arrow showing point where a speck of mould caused this DAT to rip. (Not one of The High - Martin Hannett tapes, but one previously brought to Greatbear in this state!)
Disassembly: unscrewing The High DAT cassette shell to access tape inside
restoration
We've found the safest way to restore mould-stricken DAT cassettes to a playable state and avoid ripping is to:
Acclimatise the tape to the controlled temperature and humidity of the Greatbear studio, driving the mould spores to dormancy
Disassemble the cassette shell
Very slowly and carefully unwind and rewind the tape by hand, dislodging the 'sticky' mould
Re-house the spools in a new, clean shell
Digitise via multiple passes, cleaning the DAT machine between plays. For these tapes we used our Sony PCM 7040
Sony ceased production of new DAT machines in 2005, and working, professional machines are becoming rare. We spend a considerable (and usually enjoyable) amount of time and resources keeping our machines in good condition. The Sony PCM 7040 is one of the better DAT machines in terms of the robustness of the tape transport and machine parts availability, as the same transport system was used in many Sony DDS DAT drives used in computer backup.
The High - Martin Hannett Sessions DAT master shell open with white mould visible on surface of tape pack
DAT during manual unwinding, showing mould-induced tendency for tape to stick to itself
The problem of mould growth on DATs is not unique to these precious Hannett / The High recordings.
Most DATs are now between 20 - 30 years old, and it only takes one period of storage at high temperature and/or relative humidity (RH) for mould to set in. To avoid damage, magnetic tape must be stored consistently at levels of 18 - 21 °C, and at 45 - 50% RH - something which no garage, attic or back room can guarantee...
We regularly receive mouldy DATs at the Greatbear studio. So much important material was mastered to DAT in the 1990s, and its vulnerabilities make it a priority for digitisation.
Support your local independent record shop on Record Store Day and every day!
The effects of mould growth on both the integrity of the tape and the recorded sound or image can be significant.
Mould growth often sticks the tape layers in a tightly packed reel together often at one edge. If an affected tape is wound or played this can rip the tape.
DAT audio cassette shell opened to reveal visible mould on edge of tape pack
DVCPRO video cassette lid lifted to show tape split longitudinally
If the mould has damaged the record side of the tape then the magnetic tracks are usually damaged and signal loss will result. This will create audible and visual artefacts that cannot be resolved.
Mould develops on tapes that have been stored in less-than-optimum conditions. Institutional collections can exhibit mould growth if they have not have been stored in a suitable, temperature controlled environment. For magnetic tape collections this is recommended at 15 +/- 3° C and 40% maximum relative humidity, although the British Library's Preservation Advisory Centre suggest 'the necessary conditions for [mould] germination are generally: temperatures of 10-35ºC with optima of 20ºC and above [and] relative humidities greater than 70%.'
For domestic and personal collections the mouldy tapes we receive are often the ones that have been stored in the shed, loft or basement, so be sure to check the condition of anything you think may be at risk.
We do come across cases where mould is not easily visble to the naked eye without dismantling a cassette shell - so unless you can be sure your tape has been kept in optimum storage conditions for its entire 'life', it's better to err on the side of caution. Playing a mould-affected tape in a domestic machine can very easily damage the tape.
It is important to remember that a mouldy tape is a hazard not just for the individual tape. If not handled carefully it can potentially spread to other parts of your collection, so must be treated immediately.
filaments of mould on Hi8 video tape edge
Hi8 tape showing longitudinal tear caused by sticking
There are several stages to our treatment of your mouldy tape.
Firstly, if the mould is still active it has to be driven into dormancy. You will be able to tell if there is active mould on your tape because it will be moist, smudging slightly if it is touched. If the tape is in this condition there is a high risk it will infect other parts of your collection. We strongly advise you to quarantine the tape (and of course wash your hands because active mould is nasty stuff).
When we receive mouldy tape we place it in a sealed bag filled with desiccating silica gel. The silica gel helps to absorb the tape's moisture and de-fertilises the mould's 'living environment'.
When the mould becomes dormant it will appear white and dusty, and is relatively easy to treat at this stage. We use brushes, vacuums with HEPA filters and cleaning solutions such as hydrogen peroxide to clean the tape.
Treatment should be conducted in a controlled environment using the appropriate health protections such as masks and gloves because mould can be very damaging for health.
All machines used to playback mouldy tape are cleaned thoroughly after use - even tapes with dormant mould still carry the risk of infection.
Most tapes-infested with mould are treatable and can be effectively played back following the appropriate treatment procedures. Occasionally mould growth is so extensive however that it damages the binder irreparably. Mould can also exacerbate other problems associated with impaired tape, such as binder hydrolysis.
gently dislodging mould from U-matic video tape
Edge and upper-surface mould causing U-matic video tape to stick
When it comes to tape mould the message is simple: it is a serious problem which poses a significant risk to the integrity of your collection.
If you do find mould on your tapes all is not lost. With careful, specialised treatment the material can be recovered. Action does need to be taken promptly however in order to salvage the tape and prevent the spread of further infection.
Feel free to contact us if you want to talk about your audio or video tapes that may need treatment or assessment.
The binder is crucial part of the composition of audio and video magnetic tape. It holds the iron oxide magnetisable coating on to its plastic carrier and facilitates its transport through the playback mechanism. It is also, however, 'universally agreed that with modern PET-based tape the binder is the weak link, and is generally the part of the tape which creates the most problems,' according to a UNESCO report.
There is of course no 'one-size-fits-all' answer to treating problems with tape binder. Each tape will have a unique manufacturing, playback and storage history that will shape its current condition, so restoration solutions need to respond on a case-by-case basis.
Detailed below are some of the common and diverse things that can go wrong with the tape binder, and how Greatbear can help restore your tape to a playable condition.
Binder Hydrolysis aka Sticky Shed Syndrome and Tape Baking
Probably the most well-known fault that can occur with magnetic tape is binder hydrolysis.
As its name indicates, hydrolysis is a chemical process caused by the absorption of water present in the tape's storage environment. In certain brands of tape, most notably Ampex, the binder polymers used in magnetic tape construction are broken apart as they react with water, which causes damage to the tape.
There are other theories about what happens when tapes get sticky and shed. Dietrich Schüller conducted interviews with experts of former tape manufacturers based in Germany, and concluded that 'the chemical recipe is the basis, if not the guarantee, for tape quality and stability. The production process, is equally, if not more essential.'
Schüller's research explains how the manufacture of tapes required a delicate balance between speed and precision, encompassing issues such as coating speed, proper dispersion of components, temperature and pressure of calendars. Professional tapes were produced at a rate between 100-200 metres per second (m/s). In the final stage of tape manufacture 'production speed reached 1000 m/s. This required the cross linking of binder components during the coating process.' This uneven distribution, Schüller found, sometimes led to sticky areas. [1]
Tapes exhibiting sticky shed syndrome will stick to the tape pack as they are unwound. These tapes are extremely vulnerable and need effective treatment before they can be played back. Playing a sticky tape is likely to damage the tape. It will also result in head clogs, stick-slip playback and seizure of the tape transport. In extreme cases the tape may fall apart entirely.
Although a serious problem, binder hydrolysis can be treated. Tape baking at controlled temperatures can temporarily improve binder integrity, helping to restore tape to a playable condition. In our studios we use a Thermo Scientific Heraeus B20 laboratory incubator for this process.
Lubricant Loss
Lubricants are a crucial part of the tape binder's composition, required to help the tape move smoothly through the transport. 'The quantity of lubricant is greater for video than for audio because of the higher writing and reading speeds.' [2]
Over time, the level of lubricant in the tape decreases because lubricants are partially consumed every time the tape is played. Lubricant levels decrease over time even if they are unplayed, particularly if they have not been stored in appropriate conditions for passive preservation.
As you will imagine, playing a tape back that has lost its lubricant carries with it certain risks. The tape may seize in the transport as a result of high friction, and the magnetic coating may be torn off the tape backing as it moves at a high speed past the tape head.
In cases where there is extreme lubricant loss we can apply a lubricant to help ease the tape through the transport. On the whole we are keen to use treatment methods that are as non-intrusive as possible, so such measures are kept to a minimum: 're-lubrication [...] must be seen very critically, as it is impossible to restrict added lubricants to the small amounts actually needed. Superfluous lubricants are difficult to remove from the tape guides, heads, and capstan and may interact with other tapes played on those machines at a later date.' [3]
A lack of lubricant can often result in dry shedding. This produces a dusty (rather than sticky) residue that is deposited on the capstan belts and pinch rollers as the tape moves through the transport. Dry shedding can be treated by consistently cleaning the tape until it reaches a point where it can be played back without shedding again. You can read more about this method here.
[1] Dietrich Schüller, 'Magnetic Tape Stability: Talking to Experts of Former Tape Manufacturers.' IASA Journal, Vol. 42, Jan 2014, 32-37, 34.
[2] IASA-TC-05, 'Handling and Storage of Audio and Video Carriers,' 20.
[3] IASA-TC-05, 'Handling and Storage of Audio and Video Carriers,' 20.
Assessment and treatment is an
important part of Greatbear’s audiovisual preservation work. Even before a tape is played back we need to ensure it is in optimum condition. Sometimes it is possible to make a diagnosis through visual assessment alone. A tape we received recently, for example, clearly displayed signs of ‘spoking.’
Spoking is a term used in the AV preservation world to describe the deformation of the tape pack due to improper winding, storage or a badly set up machine. The National Archives describe it as a ‘condition of magnetic tape and motion picture film where excessive pressure caused by shrinkage or too much winding tension eventually causes deformation.’
In our experience ‘spoking’ predominantly occurs with domestic open reel tapes. We have rarely seen problems of this nature with recordings made in professional settings. Compared with professional grade tape, domestic open reel tape was often thinner, making it cheaper to produce and buy.
‘Spoking’ in domestic tape recordings can also be explained by the significant differences in how tape was used in professional and domestic environments.
Domestic tape use was more likely to have an ‘amateur’ flavour. This does not mean that your average consumer did not know what they were doing. Nor were they careless with the media they bought and made. It cannot be denied, however, that your average domestic tape machine would never match the wind-quality of their professional counterparts.
In contrast, the only concern of recording professionals was to make a quality recording using the best tape and equipment. Furthermore, recording practices would be done in a conscientious and standardised manner, according to best industry practice.
The majority of ‘spoking’ cases we have seen are in acetate-backed tape which tends to become inflexible – a bit like an extended tape measure – as it ages. The good news is that it is relatively easy to treat tapes suffering from ‘spoking’ through careful – and slow – re-winding.
Slowly winding the tape at a controlled tension, colloquially known as ‘library wind’, helps relieve stress present in the pack. The end result is often a flatter and even wound tape pack, suitable for making a preservation transfer.
We recently received a fascinating collection of tapes from the archive of Robert Chenciner, an ethnographer with over thirty years experience studying the cultures, human rights and current affairs of Daghestan.
Daghestan is located in the north Caucasus region, its neighbouring countries are Azerbaijan, Chechnya and Georgia, while its eastern border is flanked by the Caspian Sea.
In the early 1980s Robert had unique access to Daghestan and other parts of the Soviet Caucasus in the twilight years of the USSR.
During visits Robert made recordings of Daghestan’s rich culture. This included music, documenting ethnic instruments such as the Chagana, as well as singing and dancing.
Although Robert believes that claims to authenticity must be treated with suspicion, he nonetheless told me that these recordings document the traditional folk culture that was practiced in the villages of Daghestan.
These tapes also document the 31 mutually unintelligible languages spoken in Daghestan such as Avar which is spoken by 900,000 people.
Listen to excerpt of a tape from the collection. The tape had experienced mould growth and had snapped. It therefore needed to be repaired prior to transfer. Robert explains: ‘The recording was made in Untsukul c.March 1990. You can hear Russian being spoken with a heavy accent, some Kumyk and some Avar. It was joking and talk about who was I and where from.’
Type IV Metal Cassettes
When Robert travelled to Daghestan he was keen to get the most professional recordings he could. For this reason he used type IV metal audio cassette tapes, a tape formula that had been introduced in the late 1970s to offer better quality recordings.
‘had been adopted by a lot of enthusiasts. They remained too expensive to be bought in bulk by the average consumer, but if you wanted to record something special – and particularly if you produced music yourself – you’d probably be highly attracted by the exceptional recording quality of a good metal cassette.’
The science behind the type IV cassette, according to the Museum of Obsolete Media, was to use ‘pure metal particles instead of metal oxides. This created a hard-wearing tape with superior frequency response and greater dynamic range.’
Since completing the recordings in the mid 1980s, as with so many of the tapes we receive at Greatbear, they have been tucked away in a drawer and out of circulation.
Another problem some tapes exhibited was the degradation of the foam pressure pad. This had ‘stuck’ onto the tape and stopped it it from playing. In one case the tape had snapped as a result from a previous attempt at playback.
Fortunately this issue did not effect our ability to do the transfer. We use Nakamichi tape decks to do optimal audio cassette transfers. The transport design within Nakamichi machines doesn’t use the tape pressure pad to play back the tapes. This is because, Wikipedia tells us,
‘Nakamichi found that this pad provided uneven and fairly inaccurate pressure and was therefore inadequate for reliable tape/head contact. Furthermore, Nakamichi found that the pressure pad was a source of audible noise, particularly scrape flutter (the tape bouncing across the head, a result of uneven pressure), and also contributed to premature head wear. Nakamichi’s dual-capstan tape decks provide such accurate and precise tape tension that, unlike other decks, the cassette’s pressure pad is not needed at all.’
The insides of a Nakamichi machine that has no need of a pressure pad to play back tapes.
Re-publication plans
Recent interest from musicologist Stefan Williamson-Fa, the driving force behind getting the tapes transferred to digital files with Great Bear, will enable these unique recordings to be heard by new audiences.
These include what Robert believes to be the only recording of an Andi Zikr ritual. Banned by the Tsar and later the Soviets, the Zikr ritual proved to be a resilient part of Daghestan’s Sufi culture. Zikr involves a group rotating in a circle, stamping the ground and grunting in order to create a mystical and ecstatic experience.
Stefan and Robert have plans to make the transferred digital files available online.
Robert reflected that when he was collecting the tapes in the 1980s his imagined audience for the recordings was pretty small. With the possibility of online publication this audience has substantially increased.
Furthermore, through people uploading material to sites such as YouTube the amount of Daghestan’s culture that can be accessed on the internet continues to grow. Robert’s links with the academic community in Daghestan also means the recordings will gain exposure there as well.
It is no doubt that those interested in the cultural history of Daghestan will await the publication of these recordings with much excitement. When the website is available we will of course let you know!
***Many thanks to Robert Chenciner for talking to us about his collection, and to Stefan for putting us in touch***
One of the most interesting aspects of digitising magnetic tapes is what happens to them after they leave the Greatbear studio. Often transfers are done for private or personal interest, such as listening to the recording of loved ones, or for straightforward archival reasons. Yet in some cases material is re-used in a new creative project, thereby translating recordings within a different technical and historical context.
Walter Benjamin described such acts as the ‘afterlife’ of translation: ‘a translation issues from the original not so much for its life as from its afterlife […] translation marks their stage of continued life.’ [1]
Part of the vanguard movement of radical arts organisations that emerged in the late 1960s, Action Space described themselves as ‘necessarily experimental, devious, ambiguous, and always changing in order to find a new situation. In the short term the objectives are to continually question and demonstrate through the actions of all kinds new relationships between artists and public, teachers and taught, drop-outs and society, performers and audiences, and to question current attitudes of the possibility of creativity for everyone.’ [2]
Such creative shape-shifting, which took its impulsive artistic action in a range of public spaces can so often be the enemy of documentation.
Yet Ken Turner, who founded Action Space alongside Mary Turner and Alan Nisbet, told me that ‘Super Eight film and transparency slides were our main documentation tools, so we were aware of recording events and their importance.’
Action Space were part of this wave of audiovisual adoption (minor of course by today’s standards!)
After ‘accidentally’ inheriting a Portapak recorder from the Marquis of Bath, Ken explained, Action Space ‘took the Portapak in our stride into events and dramas of the community festivals and neighbourhood gatherings, and adventure playgrounds. We did not have an editing deck; as far as I can remember played back footage through a TV, but even then it had white noise, if that’s the term, probably it was dirty recording heads. We were not to know.’
Preservation issues
Yes those dirty recording heads make things more difficult when it comes to re-formatting the material.
While some of the recordings replay almost perfectly, some have odd tracking problems and emit noise, which are evidence of a faulty recorder and/or dirty tape path or heads. Because such imperfections were embedded at the time of recording, there is little that can be done to ‘clean up’ the signal.
Other problems with the Action Space collection arise from the chemical composition of the tapes. The recordings are mainly on Sony branded V30H and high density V60H tape which always suffer from binder hydrolysis. The tapes therefore needed ‘baking’ treatment prior to transfer usually (we have found) in a more controlled and longer way from Ampex branded tapes.
And that old foe of magnetic tape strikes again: mould. Due to being stored in an inappropriate environment over a prolonged period, many of the tapes have mould growth that has damaged the binder.
Despite these imperfections, or even because of them, Ken appreciates the unique value of these recordings: ‘the footage I have now of the community use reminds me of the rawness of the events, the people and the atmosphere of noise and constant movement. I am extremely glad to have these tapes transposed into digital footage as they vividly remind me of earlier times. I think this is essential to understanding the history and past experiences that might otherwise escape the memories of events.’
Historical translation
While the footage of Action Space is in itself a valuable historical document, the recordings will be subject a further act of translation, courtesy of Ken’s film maker son, Huw Wahl.
Fresh from the success of his film about anarchist art critic and poet Herbert Read, Huw is using the digitised tapes as inspiration for a new work.
This new film will reflect on the legacies of Action Space, examing how the group’s interventions can speak to our current historical context.
Huw told me he wants to re-animate Action Space’s ethos of free play, education and art in order ‘to question what actions could shape a democratic and creative society. In terms of the rhetoric of creativity we hear now from the arts council and artistic institutions, it’s important to look at where that developed from. Once we see how radical those beginnings really were, maybe we will see more clearly where we are heading if we continue to look at creativity as a commodity, rather than a potent force for a different kind of society.’
Inflatable action
Part of such re-animation will entail re-visiting Action Space’s work with large inflatable structures, or what Ken prefers to call ‘air or pneumatic structures.’
Huw intends to make a new inflatable structure that will act as the container for a range of artistic, academic, musical and nostalgic responses to Action Space’s history. The finished film will then be screened inside the inflatable, creating what promises to be an unruly and unpredictable spectacle.
Ken spoke fondly about the video footage which recorded ‘the urgency of “performance” of the people who are responding to the inflatables. Today inflatable making and use is more controlled, in the 60s control was only minimally observed, to prevent injuries. But in all our activities over 10 years of air structure events, we had only one fractured limb.’
Greatbear cameo!
Another great thing about the film is that the Greatbear Studio will have an important cameo role.
Huw came to visit us to shoot footage of the transfers. He explains his reasons:
‘I’d like viewers to see the set up for the capturing of the footage used in the film. Personally it’s very different seeing the reel played on a deck rather than scanning through a quicktime file. You pay a different kind of attention to it. I don’t want to be too nostalgic about a format I have never shot with, yet there seems to be an amateur quality inherent to the portapak which I assume is because the reels could be re-recorded over. Seeing material shot by children is something the super 8mm footage just doesn’t have, it would have been too expensive. Whereas watching children grabbing a portapack camera and running about with it is pretty exciting. Seeing the reels and machines for playing it all brings me closer to the experience of using the actual portapak cameras. Hopefully this will inform the filming and editing process of this film.’
We wish Huw the very best for his work on this project and look forward to seeing the results!
***Big thanks to Ken Turner and Huw Wahl for answering questions for this article.***
Notes
[1] Walter Benjamin, ‘The Task of the Translator,’ Selected Writings: 1913-1926, Volume 1, Harvard University Press, 2006, 253-264, 254.
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.
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.
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.
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.
We understand that when organisations decide to digitise magnetic tape collections the whole process can take significant amounts of time. From initial condition appraisals, to selecting which items to digitise, many questions, as well as technical and cultural factors, have to be taken into account before a digital transfer can take place.
This is further complicated by that fact that money is not readily available for larger digitisation projects and specific funding has to be sought. Often an evidence base has to be collected to present to potential funders about the value and importance of a collection, and this involves working with organisations who have specific expertise in transferring tape-based collections to digital formats to gain vital advice and support.
We are very happy to work with organisations and institutions during this crucial period of collection assessment and bid development. We understand that even during the pre-application stage informed decisions need to be made about the conditions of tape, and realistic anticipations of what treatments may be required during a particular digitisation project. We are very willing to offer the support and advice that will hopefully contribute to the development of a successful bid.
For example, we recently were contacted by Ken Turner who was involved in Action Space, an experimental, community theatre group established in 1968. Ken has a collection of nearly 40 EIAJ SONY video tapes that were made in the 1980s. Because of the nature of the tapes, which almost always require treatment before they can be played back, transferring the whole collection will be fairly expensive so funding will be necessary to make the project happen. We have offered to do a free assessment of the tapes and provide a ten minute sample of the transfer that can be used as part of an evidence base for a funding bid.
Potential Problems with EIAJ ½ Video Tapes
The EIAJ video tape recorder was developed in the late 1960s and is a fairly important format in the history of recordable media. As the first standardized video tape machine, it could playback tapes made by different companies and therefore made video use far cheaper and more widespread, particularly within a domestic context. The EIAJ standard had a similar democratising impact on non-professional video recording due to its portability, low cost, and versatility.As mentioned above, the EIAJ tapes almost always require treatment before they can be played back, particularly the SONY V30-H and V60-H tapes. Problems with the tape are indicated by squealing and shedding upon playback. This is an example of what the AV Artifact Atlas describe as stiction, ‘when media suffering from hydrolysis or contamination is restricted from moving through the tape path correctly.’ When stiction occurs the tape needs to be removed from the transport and treated immediately, either through baking and cleaning, before the transfer can be completed.
EIAJ tapes that have a polyethylene terephthalate ‘back coating’ or ‘substrate’ may also be affected by temperature or humidity changes in its storage environment. These may have caused the tape pack to expand or contract, therefore resulting in permanent distortion of the tape backing. Such problems are exacerbated by the helical scan method of recording which is common to video tape, which records parallel tracks that run diagonally across the tape from one edge to the other. If the angle that the recorded tracks make to the edge of the tape do not correspond with the scan angle of the head (which always remains fixed), mistracking and information loss can occur, which can lead to tracking errors. Correcting tracking errors is fairly easy as most machines have in-built tracking controls. Some of the earliest SONY CV ½ inch video tape machines didn’t have this function however, so this presents serious problems for the migration of these tapes if their back coating has suffered deformation.
The possibility of collaboration
We are excited about the possibility of working with the Action Space collection, mainly because we would love to opportunity to learn more about their work. Like many other theatre groups who were established in the late 1960s, Action Space wanted to challenge the elitism of art and make it accessible to everyone in the community. In their 1972 annual report, which is archived on the Unfinished Histories: Recording the History of Alternative Theatre website, they describe the purposes of the company as follows:
‘Its workings are necessarily experimental, devious, ambiguous, and always changing in order to find a new situation. In the short term the objectives are to continually question and demonstrate through the actions of all kinds new relationships between artists and public, teachers and taught, drop-outs and society, performers and audiences, and to question current attitudes of the possibility of creativity for everyone. For the longer term the aim is to place the artists in a non-elite set up, to keep “normal” under revision, to break barriers in communication and to recognise that education is a continuing process.’
Although Action Space disbanded in 1981, the project was relaunched in the same year as Action Space Mobile, who are still operating today. The centre of the Action Space Mobile’s philosophy is that they are an arts company ‘that has always worked with people, believing that contact and participation in the arts can change lives positively.’ There is also the London based ActionSpace, who work with artists with learning disabilities.
We hope that offering community heritage projects the possibility of collaboration will help them to benefit from our knowledge and experience. In turn we will have interesting things to watch and listen to, which is part of what makes working in the digitisation world fun and enjoyable.
Often the tapes we receive to digitise are ‘forgotten’ recordings. Buried under a pile of stuff in a dark, cold room, their owners think they are lost forever. Then, one day, a reel of the mysterious tape emerges from the shadows generating feelings of excitement and anticipation. What is stored on tape? Is the material in a playable condition? What will happen to the tape once it is in a digital format?
All of these things happened recently when Paul Travis sent us a ¼ inch AMPEX tape of the band he played in with his brother, the Salford Oi! punk outfit State Victims. The impetus for forming State Victims emerged when the two brothers ‘split from Salford bands, Terrorist Guitars and the Bouncing Czechs respectively, and were looking for a new musical vessel to express and reassert their DIY music ethic, but in a more vital and relevant way, searching for a new form of “working-class protest.”‘
The tape had been in the wilderness for the past 30 years, residing quietly in a shed in rural Cambridgeshire. It was in fairly good condition, displaying no signs of damage such as mould on the tape or spool. Like many of the AMPEX tapes we receive it did need some baking treatment because it was suffering from binder hydrolysis (a.k.a. Sticky Shed Syndrome). The baking, conducted at 49 Celsius for 8 hours in our customised oven, was successful and the transfer was completed without any problems. We created a high resolution stereo 24 bit/ 96 kHz WAV file which is recommended for archived audio, as well as a MP3 access copy that can be easily shared online.
Image of tape post-transfer. When it arrived the tape was not wound on neatly and there was no leder tape on it.
Finding old tapes and sending them to be digitised can be a process of discovery. Originally Paul thought the tape was of a 1983 session recorded at the Out of the Blue Studios in Ancoats, Manchester, but it became apparent that the tape was of an earlier recording. Soon after we digitised the first recording we received a message from Paul saying another State Victims tape had ‘popped up in an attic’, so it is amazing what you find when you start digging around!
Like many other bands connected to the Manchester area, the digital artefacts of State Victims are stored on the Manchester District Music Archive (MDMA), a user-led online archive established in 2003 in order to celebrate Greater Manchester music and its history. The MDMA is part of a wider trend of do it yourself archival activity that exploded in the 21st century due to the availability of cheap digital technologies. In what is arguably a unique archival moment, digital technologies have enabled marginal, subcultural and non/ anti-commercial music to widely circulate alongside the more conventional, commercial artefacts of popular music. This is reflected in the MDMA where the artefacts of famous Manchester bands such as The Smiths, The Fall, Oasis and Joy Division sit alongside the significantly less famous archives of the Manchester Musicians Collective, The Paranoids, Something Shady and many others.
Within the community-curated space of the MDMA all of the artefacts acquire a similar value, derived from their ability to illuminate the social history of the area told through its music. Much lip service has been paid to the potential of Web 2.0 technologies and social media to enable new forms of collaboration and ‘user-participation’, but involving people in the construction of web-based content is not always an automatic process. If you build it, people do not always come. As a user-led resource, however, the MDMA seems pretty effective. It is inviting to use, well organised and a wide range of people are clearly contributing, which is reflected in the vibrancy of its content. It is exciting that such an online depository exists, providing a new home for the errant tape, freshly digitised, that is part of Manchester’s music history.
What a year it has been in the life of Greatbear Analogue and Digital Media. As always the material customers have sent us to digitise has been fascinating and diverse, both in terms of the recordings themselves and the technical challenges presented in the transfer process. At the end of a busy year we want to take this opportunity to thank our customers for sending us their valuable tape collections, which over the course of 2013 has amounted to a whopping 900 hours of digitised material.
We feel very honoured to play a part in preserving personal and institutional archives that are often incredibly rare, unique and, more often than not, very entertaining. It is a fairly regular occurrence in the Great Bear Studio to have radio jingles from the 60s, oral histories of war veterans, recordings of family get-togethers and video documentation of avant-garde 1970s art experiments simultaneously migrating in a vibrant melee of digitisation.
We have also received a large amount of rare or ‘lost’ audio recordings through which we have encountered unique moments in popular music history. These include live recordings from the Couriers Folk Club in Leicester, demo tapes from artists who achieved niche success like 80s John Peel favourites BOB, and large archives of prolific but unknown songwriters such as the late Jack Hollingshead, who was briefly signed to the Beatles’ Apple label in the 1960s. We always have a steady stream of tapes from Bristol Archive Records, who continue to acquire rare recordings from bands active in the UK’s reggae and post-punk scenes. We have also migrated VHS footage of local band Meet Your Feet from the early 1990s.
On our blog we have delved into the wonderful world of digital preservation and information management, discussing issues such as ‘parsimonious preservation‘ which is advocated by the National Archives, as well as processes such as migration, normalisation and emulation. Our research suggests that there is still no ‘one-size-fits-all’ strategy in place for digital information management, and we will continue to monitor the debates and emerging practices in this field in the coming year. Migrating analogue and digital tapes to digital files remains strongly recommended for access and preservation reasons, with some experts bookmarking 15 April 2023 as the date when obsolescence for many formats will come into full effect.
We have been developing the blog into a source of information and advice for our customers, particularly relating to issues such as copyright and compression/ digital format delivery. We hope you have found it useful!
While the world is facing a growing electronic waste crisis, Great Bear is doing its bit to buck the trend by recycling old domestic and professional tape machines. In 2013 we have acquired over 20 ‘new’ old analogue and digital video machines. This has included early ’70s video cassette domestic machines such as the N1502, up to the most recent obsolete formats such as Digital Betacam. We are always looking for old machines, both working and not working, so do get in touch if your spring clean involves ridding yourself of obsolete tape machines!
Our collection of test equipment is also growing as we acquire more wave form monitors, rare time-based correctors and vectorscopes. In audio preservation we’ve invested heavily in early digital audio machines such as multi-track DTRS and ADAT machines which are rapidly becoming obsolete.
We are very much looking forward to new challenges in 2014 as we help more people migrate their tape-based collections to digital formats. We are particularly keen to develop our work with larger archives and memory institutions, and can offer consultation on technical issues that arise from planning and delivering a large-scale digitisation project, so please do get in touch if you want to benefit from our knowledge and experience.
Once again a big thank you from us at Greatbear, and we hope to hear from you in the new year.
We were recently sent a very interesting collection of recordings of the late poet, novelist and acclaimed translator Paul Roche. During his colourful and creative life Roche published two novels, O Pale Gallellean and Vessel of Dishonour, and several poetry collections, and brushed shoulders with some of the 20th century’s most captivating avant-garde artistic and literary figures. His faculty colleague when he worked at Smith College, MA in the late 1950s was none other than Sylvia Plath, who pithily described Roche’s ‘professional dewy blue-eyed look and his commercially gilded and curled blond hair on his erect, dainty bored aristocratic head’.
His intense 30 year friendship with painter Duncan Grant was immortalised in the book With Duncan Grant in Southern Turkey, which documented a holiday the friends took together shortly before Grant’s death. The relationship with Grant has often eclipsed Roche’s own achievements, and he is often mistakenly identified as a member of the Bloomsbury group. Roche also achieved success beyond the literary and scholarly world when his translation of Oedipus the King became the screenplay for the 1968 film starring Christopher Plummer and Orson Welles.
The recordings we were sent were made between 1960-1967 when Roche worked at universities in America. Roche experienced greater professional success in America, and his translations of Ancient Greek are still used in US schools and universities. His son Martin, who sent us the tapes, is planning to use the digitised recordings on a commemorative website that will introduce contemporary audiences to his father’s creative legacy.
The Great Bear Studio has been pleasantly awash today with the sound of Roche reading poetry and his dramatic renditions of Sophocles’ ‘Oedipus the King’, ‘Oedipus at Colonus’ and ‘Antigone’. The readings communicate his emphatic pleasure performing language via the spoken word, and an unique talent to immerse listeners in images, rhythm and phrases.
Listen to Paul Roche reading his translation of ‘Antigone’.
Our own pleasure listening to the recordings has however been disrupted because of frequent snaps in the tape. The tapes are covered in splices, which suggests they had been edited previously. Over time the adhesive glue has dried out, breaking the tape as it moves through the transport. The collection of tapes as a whole are fairly brittle because the base film, which forms the structural integrity of the tape, is made of acetate.
Canadian-based digitisation expert Richard Hess explains that
‘Acetate was the first widely used base film, with Scotch 111 being in production from 1948 through 1972/73, a total of 24-25 years. Acetate tape is generally robust and has the advantage of breaking cleanly rather than stretching substantially prior to breaking when overstressed. Acetate tapes residing in collections are over 30-years-old, with the oldest being over 60-years-old.’
The big downside to acetate is that when it degrades it loses its flexibility and becomes a bit like an extended tape measure. This means it is harder to pass the tape consistently through the tape transport. This is colloquially known in the digitisation world as ‘country-laning’, when the tape changes shape in all dimensions and becomes wiggly, like a country lane. To extend the metaphor, a well functioning tape should be flat, like, one supposes, a motorway.
When a tape is ‘country-laning’ it means tracks of recorded material are moving slightly so they shift in and out of phase, dis-aligning the angle between the tape head(s) and tape, or azimuth. This has a detrimental effect on the quality of the playback because the machine reading the recorded material on the tape is at odds with surface area from which the information is being read.
If you are reading this and wondering if the base film in your tape is made of acetate, or is made of another substance such as paper or polyester, you can perform a simple test. If you hold the tape against the light and it appears translucent then the tape is acetate. There may also be a slightly odd, vinegar smell coming from the tape. If so, this is bad news for you because the tape is probably suffering from ‘Vinegar Syndrome’. Richard Hess explains that
‘Vinegar syndrome occurs as acetate decomposes and forms acetic acid. This is a well-known degradation mode for acetate film. High temperature and humidity levels, the presence of iron oxide, and the lack of ventilation all accelerate the process. Once it has started it can only be slowed down, not reversed.’
Acetate tape is also particularly vulnerable to excessive heat exposure, which makes it shrink in size. This is why you should never bake acetate tape! When acetate tape is exposed to heat it reaches what is known as the liquid-glass transition phase, the temperature where the material composition starts to change shape from a hard and relatively brittle state into a molten or rubber-like state. Although glass transition is reversible, it certainly is destructive. In other words, you can change the tape back from molten to a hard substance again but the tape would be unplayable.
While acetate backed tape has certain advantages over polyester tape in the migration process, namely it is easier to cleanly splice together tape that has broken as it has moved through the transport, unfortunately acetate tape is more fragile, and can get extremely stiff which makes it difficult to play back the tape at all. Even if you can pass the tape through the machine it may snap regularly, and will therefore require a lot of treatment in the transfer process. So if you have a valuable tape collection stored predominantly on acetate tape, we strongly recommend getting it migrated to digital format as soon as possible due to the fragility of the format. And if that whiff of vinegar is present, you need to move even more quickly!
An important part of digitisation work we do is tape restoration. Often customers send us tape that have been stored in less than ideal conditions that are either too hot, cold or damp, which can lead to degradation.
In the excellent Council on Library and Information Sources’ report on Magnetic Storage and Handling (1995), they set the ideal archival storage conditions for magnetic tape at ‘significantly lower than room ambient (as low as 5 centrigade)’, with no less than 4 degrees variation in temperature at 20% room humidity. They suggest that ‘the conditions are specifically designed to reduce the rate of media deterioration through a lowering of the temperature and humidity content of the media.’
Of course most people do not have access to such temperature controlled environments, or are necessarily thinking about the future when they store their tape at home. Sometimes manufacturers recommended to store tape in a ‘cool, dark place’, but often tape is not adorned with any such advice. This leads to us receiving a lot of damaged tape!
As we are keen to emphasise to customers, it is possible to salvage most recordings made on magnetic analogue tape that appear to be seriously damaged, it just requires a lot more time and attention.
For example, we were recently sent a collection of 3” multi-track tapes that had been stored in fairly bad conditions. Nearly all the tapes were degraded and needed to be treated. A significant number of these tapes were AMPEX so were suffering from binder hydrolysis, a.k.a. sticky shed syndrome in the digitisation world. This is a chemical process where binder polymers used in magnetic tape constructions become fragmented because the tape has absorbed water from its immediate environment. When this happens tapes become sticky and sheds when it is played back.
Baking the AMPEX tapes is a temporary treatment for binder hydrolysis, and after baking they need to be migrated to digital format as soon as possible (no more than two weeks is recommended). Baking is by no means a universal treatment for all tapes – sticky shed occurs due to the specific chemicals AMPEX used in their magnetic tape.
Cleaning shedding tape
Other problems occur that require different kinds of treatment. For example, some of the 3” collection weren’t suffering from sticky shed syndrome but were still shedding. We were forewarned by notes on the box:
The tapes recorded on TDK were particularly bad, largely because of poor storage conditions. There was so much loose binder on these tapes that they needed cleaning 5 or 6 times before we could get a good playback.
We use an adapted Studer A80 solely for cleaning purposes. Tape is carefully wound and rewound and interlining curtain fabric is used to clean each section of the tape. The photo below demonstrates the extent of the tape shedding, both by the dirty marks on fabric, and the amount we have used to clean the collection.
You might think rigorous cleaning risks severely damaging the quality of the tape, but it is surprising how clear all the tapes have sounded on playback. The simple truth is, the only way to deal with dry shedding is to apply such treatment because it simply won’t be able to playback clearly through the machine if it is dirty.
Loss of lubricant
Another problem we have dealt with has been the loss of lubricant in the tape binder. Tape binder is made up of a number of chemicals that include lubricant reservoirs, polymers and magnetic particles.
Lubricants are normally added to the binder to reduce the friction of the magnetic topcoat layer of the tape. Over time, the level of the lubricant decreases because it is worn down every time the tape is played, potentially leading to tape seizures in the transport device due to high friction.
In such circumstances it is necessary to carefully re-lubricate the tape to ensure that it can run smoothly past the tape heads and play back. Lubrication must be done sparingly because the tape needs to be moist enough to function effectively, but not too wet so it exacerbates clogging in the tape head mechanism.
Restoration work can be very time consuming. Even though each 3″ tape plays for around 20 minutes, the preparation of tapes can take a lot longer.
Another thing to consider is these are multi-track recordings: eight tracks are being squeezed onto a 1/4″ tape. This means that it only takes a small amount of debris to come off, block the tape heads, dull the high frequencies and ultimately compromise the transfer quality.
It is important, therefore, to ensure tapes are baked, lubricated or cleaned, and heads are clear on the playback mechanism so the clarity of the recording can realised in the transfer process.
Now we’ve explored the technical life of the tape in detail, what about the content? If you are a regular visitor to this blog you will know we get a lot of really interesting tape to transfer that often has a great story behind it. We contacted Richard Blackborow, who sent the tapes, to tell us more. We were taken back to the world of late 80s indie-pop, John Peel Sessions, do it yourself record labels and a loving relationship with an 8 track recorder.
A Short History of BOBby Richard Blackborow
Back in 1983 I was a 17 year old aspiring drummer, still at school in North London and in an amateur band. Happily for me, at that time, my eldest brother, also a keen musician, bought a small cottage in a village called Banwell, which is 20 or so miles outside of Bristol, near Weston Super Mare. He moved there to be near his work. The cottage had a big attic room and he installed a modest 8-track studio into it so that he could record his own music during his spare time. The studio was based around a new Fostex A8 reel-to-reel machine and the little mixing desk that came with it.
The equipment fascinated me and I was a regular visitor to his place to learn how to use it and to start recording my own music when he wasn’t using it.
Skip forward a couple of years and I am now 19, out of school, deferring my place at university and in a new band with an old friend, Simon Armstrong. My brother’s work now takes him increasingly abroad, so the studio is just sitting there doing nothing. Simon and I begin to write songs with the express intention of going to Banwell every time we had a decent number of tunes to record. Over the next ten years it becomes part of the routine of our lives! We formed a band called BOB in 1986, and although we still lived in London, we spent a lot of time in that small studio in Banwell – writing, recording demos, having wild parties! By this time my brother had moved to the US, leaving me with open access to his little studio.
The band BOB had modest success. John Peel was a keen fan and a great supporter, we toured loads around the UK and Europe and made lots of singles and an album or two, as well as recording 5 BBC sessions.
To cut a long story short, we loved that little studio and wrote and recorded some 300 songs over the ensuing 10 years…the studio gear finally dying in about 1995. Most recordings were for/by BOB, but I also recorded bands called The Siddeleys and Reserve (amongst others).
The tapes we recorded have been lying around for years, waiting to be saved!
Recent interest in BOB has resulted in plans to release two double CDs. The first contains a re-issued album, all the BBC sessions and a few rarities. The second CD, planned for next year, will contain all of the BOB singles, plus a whole CD of the best of those demos we recorded. It was for this reason that all of those old tapes were sent to Adrian to be transferred to digital. I now have a studio near my home in West Cornwall, close to Land’s End, where I will be mixing all the material that Great Bear have been working on. The demos map our progression from pretty rubbish schoolboy aspirants to reasonably accomplished songwriters. Some of the material is just embarrassing, but a good chunk is work I am still proud of. We were very prolific and the sheer number of reels that Adrian has transferred is testament to that. There is enough material there for a number of CDs, and only time will tell how much is finally released.
Listen to the recently transferred Convenience demo
This is a bit of a rarity! It’s the demo (recorded on the little 8-track machine in Banwell) for a BOB single that came out in 1989. It’s called Convenience and I wrote and sang it. This early version is on one of the tapes that Adrian has transferred, so, like many of the rest of the songs, it will be re-mixed this winter for digital formats and released next year.
If you want the latest news from BOB you can follow them on twitter. You can also pre-order the expanded edition of their 1991 album Leave the Straight Life Behind from Rough Trade. It will be available from the end of January 2014. A big thank you to Richard for sending us the photos, his writing and letting us include the recording too!
Metadata is data about data. Maybe that sounds pretty boring, but archivists love it, and it is really important for digitisation work.
As mentioned in the previous post that focused on the British Library’s digital preservation strategies, as well as manyotherfeatures on thisblog, it is fairly easy to change a digital file without knowing because you can’t see the changes. Sometimes changing a file is reversible (as in non-destructive editing) but sometimes it is not (destructive editing). What is important to realise is changing a digital file irrevocably, or applying lossy instead of lossless compression, will affect the integrity and authenticity of the data.
What is perhaps worse in the professional archive sector than changing the structure of the data, is not making a record of it in the metadata.
Metadata is a way to record all the journeys a data object has gone through in its lifetime. It can be used to highlight preservation concerns if, for example, a file has undergone several cycles of coding and decoding that potentially make it vulnerable to degradation.
‘technical data (info on resolution, image size, file format, version, size), structural metadata (describes how digital objects are put together such as a structure of files in different folders) and descriptive (info on title, subject, description and covering dates) with each type providing important information about the digital object.’
As the previous blog entry detailed, digital preservation is a dynamic, constantly changing sector. Furthermore, digital data requires far greater intervention to manage collections than physical objects and even analogue media. In such a context data objects undergo rapid changes as they adapt to the technical systems they are opened by and moved between. This would produce, one would speculate, a large stream of metadata.
What is most revealing about metadata surrounding digital objects, is they create a trail of information not only about the objects themselves. They also document our changing relationship to, and knowledge about, digital preservation. Metadata can help tell the story about how a digital object is transformed as different technical systems are adopted and then left behind. The marks of those changes are carried in the data object’s file structure, and the metadata that further elaborate those changes.
Like those who preserve physical heritage collections, a practice of minimal intervention is the ideal for maintaining both the integrity and authenticity of digital collections. But mistakes are made, and attempts to ‘clean up’ or otherwise clarify digital data do happen, so when they do, it is important to record those changes because they help guide how we look after archives in the long term.
We have already written about noise reduction this week, but did so without acknowledging the life of Ray Dolby, one of the inventors of video tape recording while working at Ampex and the inventor and founder of Dolby Noise Reduction, who died on 12 September 2013.
‘His noise-reduction system worked by applying a pre-emphasis to the audio recording, usually boosting the quieter passages. The reverse process was used on playback. Removing the boost – lowering the level – also removed most of the tape hiss that accompanied all analogue recordings. Of course, people did not care how it worked: they could hear the difference.’
Dolby managed to solve a clear problem blighting analogue tape recording: the high frequency noise or tape hiss inherent when recording on magnetic tape.
Like many professional recording studios from the 1960s onwards, the Great Bear Studio uses the Dolby A noise-reduction system that we use to play back Dolby A encoded tape. On the Dolby A the input signal is split into four individual frequency bands and provided 10 dB of broadband noise reduction overall.
We also have a Dolby SR system that was introduced in 1986 to improve upon analogue systems and in some cases surpass rapidly innovating digital sound technologies. Dolby SR maximises the recorded signal at all times using a complex series of filters that change according to the input signal and can account for up to 25dB noise reduction.
We have recently been sent a Sony V62 high density video tape by Barrie Hesketh. Barrie has had an active career in theatre and in 1966 he set up the Mull Little Theatre on the Isle of Mull off the West Coast of Scotland with his late wife Marianne Hesketh. Specialising in what Barrie calls the ‘imaginative use of nothing’ they toured the UK, Germany and Holland and gained a lot of publicity world wide in the process. Both Marianne and Barrie were awarded MBEs for their services to Scottish Theatre.
You can read a more detailed history of the Mull Little Theatre in this book written by Barrie.
Panasonic VTR NV-8030 EIAJ ½” reel to reel video recorder
The video tape Barrie sent us came from when he and Marianne were working as actors in residence at Churchill College at Cambridge University. Barrie and Marianne had what Barrie described as ‘academic leanings,’ gained from their time as students at the Central College of Speech and Drama in London.
In a letter Barrie sent with the tape he wrote:
‘I own a copy of a video tape recording made for me by the University of Cambridge video unit in 1979. I was researching audience/actors responses and the recording shows the audience on the top half of the picture, and the actors on the bottom half – I have not seen the stuff for years, but have recently been asked about it.’
While audience research is a fairly common practice now in the Creative Arts, in 1979 Barrie’s work was pioneering. Barrie was very aware of audience’s interests when he performed, and was keen to identify what he calls ‘the cool part’ of the audience, and find out ways to ‘warm them up.’
Recording audience responses was a means to sharpen the attention of actors. He was particularly interested in the research to identify ‘includers’. These were individuals who influenced the wider audience by picking up intentions of the performers and clearly responding. The movement of this individual (who would look around from time to time to see if other people ‘got it’), would be picked up in the peripheral vision of other audience members and an awareness gradually trickled throughout. Seeing such behaviour helped Barrie to understand how to engage audiences in his subsequent work.
Barrie’s tape would have been recorded on one of the later reel-to-reel tape machines that conformed to the EIAJ Standard.
The EIAJ-1 was developed in 1969 by the Electronic Industries Association of Japan. It was the first standardized format for industrial/non-broadcast video tape recording. Once implemented it enabled video tapes to be played on machines made by different manufacturers.
Prior to the introduction of the standard, tapes could not be interchanged between comparable models made by different manufacturers. The EIAJ standard changed all this, and certainly makes the job of transferring tapes easier for us today! Imagine the difficulties we would face if we had to get exactly the right machine for each tape transfer. It would probably magnify the problem of tape and machine obsolescence effecting magnetic tape collections.
In the Greatbear Studio we have the National Panasonic Time Lapse VTR NV-8030 and Hitachi SV-640.
Like Ampex tapes, all the Sony EIAJ tape tend to suffer from sticky shed syndrome caused by absorption of moisture into the binder of the tape. Tapes need to be dehydrated and cleaned before being played back, as we did with Barrie’s tape.
The tape is now being transferred and Barrie intends to give copies to his sons. It will also be used by Dr Richard Trim in an academic research project. In both cases it is gratifying to give the these video tapes a new lease of life through digitisation. No doubt they will be of real interest to Barrie’s family and the wider research community.
In a recent blog article on the Presto Centre website, Richard Wright argues that ‘the audiovisual collections of the 20th century were analogue, and we are now at a critical time for considering the digital future of that analogue content.’ He goes on to say, emphatically:
‘All analogue audio and video formats are obsolete. Digital content walks through walls, travels at the speed of light, can be in many places at the same time, and can (with care) be perfectly copied, again and again. So digitisation has become the solution to the obsolescence of all analogue audio and video formats.’
Although careful not to make too clinical a statement, he bookmarks 15 April 2023 as the date when analogue obsolescence really kicks in.
A major problem is finding spare parts for machines after manufacturers stop producing them. Many components were made according to very precise specifications that are hard to make from scratch. When machines and their parts wear out it will therefore be difficult, if not impossible, to keep them working.
This means that the cost of transfers will rise due to machine scarcity. At an institutional level this may lead to selective decisions about what gets digitised and what doesn’t.
Writing for music magazine The Wire, Numero Group’s Rob Sevier and Ken Shipley describe how ‘vinyl’s violent sales spike has been a lonely bright spot in what has been a 14 year deterioration in sales of recorded music’.
Yet the resilience of vinyl and other contemporary fringe uses of analogue media, such as the cassette tape and floppy disk, is not enough to stop the march of digitisation. For experts like Wright the digital future for the majority of people is inevitable, irresistible even, given how it enables collections to be open, replicable and accessible.
Yet committing to digital technologies as a preservation and access strategy does not solve our information problems, as we have been keen to stress on this blog. There is also a worrying lack of long term strategy for managing digital information, a problem which is ever more pronounced in film preservation where analogue tape is still marked as the original from which digital copies are made.
It is clear that the information we create, store and use is in transition. It probably always has been. The emergence of digital technologies has just made this a pressing issue, not only for large institutions, but for people as we go about our day to day lives.
‘Digitise now!!’ is Richard Wright’s advice – and of course we agree.
We are currently digitising a collection of U-matic Ampex KCS-20 video tapes for Keith Barnfather, the founder of Reeltime Pictures.
Reeltime Pictures are most well-known for their production of documentaries about the BBC series Doctor Who. They also made Doctor Who spin-off films, a kind of film equivalent of fan fiction, that revived old and often marginal characters from the popular TV series.
The tapes we were sent were Ampex’s U-matic video tapes. For those of you out there that have recorded material on Ampex tape be it audio or video, we have bad news for you. While much magnetic tape is more robust than most people imagine, this is not true of tape made by Ampex in the 1970s and 1980s.
Nearly all Ampex tape degrades disgracefully with age. A common outcome is ‘sticky shed syndrome,‘ a condition created by the deterioration of the binders in a magnetic tape which hold the iron oxide magnetic coating to its plastic carrier. So common was this problem with Ampex tape that the company patented the process of baking the tape (to be done strictly at the temperature 54 Centrigade, for a period of 16 hours), that would enable the tape to be played back.
In order to migrate the Ampex video tapes to a digital format they have, therefore, to be dehydrated in our incubator. This is careful process where we remove the tape from its outer shell to minimise ‘outgassing‘. Outgassing refers to the release of a gas that has become dissolved, trapped, frozen or absorbed in material. This can have significant effects if the released gas collects in a closed environment where air is stagnant or recirculated. The smell of new cars is a good example of outgassing that most people are familiar with.
When baking a tape in an enclosed incubator, it can therefore be vulnerable to the potential release of gasses from the shell, as well as the tape and its constituent material parts. Removing the shell primarily minimises danger to the tape, as it is difficult to know in advance what chemicals will be released when baking occurs.
It is important to stress that tape dehydration needs to be done in a controlled manner within a specifically designed lab incubator. This enables the temperature to be carefully regulated to the degree. Such precision cannot of course be achieved with domestic ovens (which are designed to cook things!), nor even food dehydrators, because there is very little temperature control.
So if you do have Ampex tapes, whether audio or video, we recommend that you treat them with extreme care, and if what is recorded on them is important to you, migrate them to a digital format before they almost certainly deteriorate.
The main work of Greatbear is to make analogue and digital tape-based media accessible for people living in a digital intensive environment. But once your tape-based media has been digitised, is that the end of the story? Do you never need to think about preservation again? What issues arise for information management in the future, and how do they relate to our actions in the present?
This year (2013) the National Archives in the UK are facing a huge challenge as the ’20-year rule‘, in which the government will be releasing records when they are 20 years old, instead of 30, comes into effect. A huge part of this process is the digitisation of large amounts of material so they can be easily accessible to the public.
What does this have to do with the digitisation of tape you may be wondering? Well, mostly it provides food for thought. When you read the guidelines for the National Archives’ digitisation strategy, it raises many points that are worth thinking about for everyone living inside an information intensive environment, professional archivist or not. These guidelines suggest that many of the problems people face with analogue media, for example not being able to open, play or use formats such as tape, floppy disks or even digital media, such as a cd-r, do not go away with the move toward wholesale digitisation. This is summed up nicely in the National Archive’s point about digital continuity. ‘If you hold selected digital records that are not yet due for transfer, you will need to maintain their digital continuity. This means ensuring that the records can be found, opened, understood, worked with and trusted over time and through change’. This statement encapsulates the essence of digital information management – the process whereby records are maintained and kept up to date with each technological permutation.
Later on in their recommendations they state something which may be surprising to people who assume that digitisation equates to some form of informational omnipotence: ‘Unlike paper records, digital records are very vulnerable and will not survive without active intervention. We cannot leave digital records on a shelf in an archive – they need active management and migration to remain accessible in the long term.’ These statements make clear that digital records are just as vulnerable as their analogue counterparts, which although subject to degrading, are in fact more robust than is often assumed.
What is the answer to ensuring that the data we create is usable in the future, is there an answer? It is clear on whatever format we choose to archive data there is always risk involved: the risk of going out of date, the risk of vulnerability, the risk of ‘not being able to leave them on the shelf’. Records, archives and data cannot, it seems, simply look after themselves. They have to adapt to their technological environments, as much as humans do.
We have recently completed a job for Quarry Faces, the Mendip Hills Community Heritage Project which has been funded by the Heritage Lottery Fund. Quarry Faces gave us 20 U-matic video tapes that were commissioned for a corporate video in the 1980s.
The Quarry Faces project aims to tell the industry’s story, produce teaching materials for both educational purposes and general interest, and create an archive to preserve images and memories of quarrying over time.
This video we digitised was shot by Coloroll Films of Kilmarnock in 1985, and was delivered to us on U-matic tape. It features a giant walking crusher at Foster Yeoman’s Merehead Quarry (Torr Works).
The video tapes we were sent were high band recordings, rather low band and of very good quality. One AMPEX U-matic tape however was problematic as the tape shell / mechanism had degraded over time and needed careful hand rewinding and reshelling in a known good and newer cassette shell.
When faced with damaged tape, often people automatically assume it needs dehydrating, a process that forces the moisture out of the tape through stable, precise, low temperature baking. However if this is not what is wrong with the tape, dehydrating or ‘baking‘ as it is more commonly called, may in fact damage the tape. If you bake acetate tape that was commonly used in the 1950s and 1960s for example, it would be destroy it.
Ampex filed for a patent for the correct temperature to recover Ampex tapes. The patent referred to “a typical temperature used is 54’C. and a typical effective time is 16 hours”.
The simple truth is, there is no all encompassing answer to know what happens to tape when it degrades, or when the cassette shell mechanism malfunctions, and each tape that is sent to us is of course individual. Digitisation and the art of restoring old tape is a relatively new area, and no one has yet made a machine that is able to precisely diagnose what is wrong with each individual tape when problems occur. Is the tape suffering from sticky shed syndrome or binder hydrolysis, or is it ‘vinegar syndrome’, a condition which afflicts acetate tape? Only through careful diagnostic work, which at Greatbear includes using our range of in-house test tapes, can the correct remedy be found.
This format was commonly used in education and in industry and was much cheaper than the U-matic and one inch formats.
We usually see Scotch and Sony branded tape stock in this format. The Sony tape, is absolutely unplayable and dangerously so. It becomes ‘sticky’ or suffers from binder hydrolysis as Ampex audio tape commonly does. The tape will squeal loudly on any fixed guides and often stop moving around the head drum often damaging the head tips.
This tape can be restored and recovered but must be dehydrated at a very stable and constant low temperature. We’ve found this tape takes much longer than audio tape in this process and it’s also necessary to address any tape pack slip too. Custom winding machines are essential here as winding this tape on the vintage machines necessary for playback is too aggressive.
The image to the right is a tape we received and has an uneven tape pack and a small amount of mould growth too.
After dehydrating, winding and cleaning the tape and and tape pack looks more like this:
We often get sent Digital Audio Tapes or DATs for transfer to .WAV computer files. As these recordings are already digital or ‘born digital’ the process should be straightforward. Our audio interface cards accept the SPDIF or AES digital audio stream from the DAT machine and record this as a WAV or BWAV file. This file can then be burnt as a CD or delivered digitally on a hard drive or removable media.
The big problems though come with the tape that these digital recordings are made on. The tape is only 3.81 mm wide and moves at a very slow 8.15 mm/sec. The tape is also very thin at 13 microns. The recording system and transport used is helical scan just like in video recording but with the very slow tape speed and small tape dimensions any defects or problems with the tape can result in many errors which may not be correctable by the error-correcting system of the DAT machine.
One problem we’re starting to see more and more are tapes that snap. The tape pictured above was a D120 which was never recommended by the DAT machine manufacturers but was still often used for its extended recording time. This tape snapped without warning a quarter of the way through the recording. There were no outward signs or potential problems just a sudden clean break on a diagonal.
To recover this tape it could have been spliced with splicing tape of the correct width like in analogue recording but there is a high risk if not done perfectly of irreparable damage to heads on the drum. Even with this type of repair some of the material would have been lost. A safer solution is to rehouse each spool in another shell. This lets you recover as much as possible from the tape, without the risk of head damage.
Whichever solution you decide, the DAT shell must be disassembled. A small crosshead screwdriver needs to be used to remove all the case screws. There are two hidden ones, accessed by sliding part of the cassette shell down:
You can now carefully lift both halves of the DAT shell apart, making a note of the tape path inside the shell. Be careful not to touch the tape with your bare skin as fingermarks and grease can cause head to tape contact problems and audio errors and dropouts.
We have recently worked on probably the worst looking tapes but with some of the best sounding music recordings we’ve seen for a while! A batch of 10.5″ NAB studio masters had bad tape mould growth.
Andy Leighton, owner of Bolex Brothers and music publisher of the Rocky Horror Show, found a batch of studio masters on quarter inch tape that had been growing mould for some of them over 30 years. All of these recordings had been made at the renowned Sound and Recording Mobile studios better known as SARM, later creative home of Trevor Horn.
Among these tapes was the first ever recording made at SARM in 1972 by Richard o’Brien, writer of the Rocky Horror Show, in addition to rare tracks by artists such as Kimi and Ritz.
When the tape mould was finally cleaned from the tapes and some of them baked for binder hydrolysis the quality of the recordings was very high and testament to the high quality available from analogue recording. Even though tape can be vulnerable to physical problems, it is also robust. If these had been tape-based digital recordings, in the same condition, I doubt we’d have been able to achieve the same results.
Unseen to 32 years, although there could possibly be other tapes in the vaults at Abbey Road.
This NTSC U-matic transfer to uncompressed quicktime files was a damaged tape that at some point in its life had been ‘eaten’ by a greedy U-matic machine! The tape shell also had some plastic debris inside that needed removing before it was safe to attempt loading and migration.
We often receive enquiries about audio and video tape that is not in the best condition having been stored in humid conditions, suffering from binder hydrolysis (sticky shed) or not wound on its reel well, but we were surprised when we received this tape recently.
It literally is a bag of tape! It is a cassette tape that had at some point become unspooled, probably when the cassette shell was opened for a repair. We can and did restore the tape by respooling and reshelling before playing on one of our Nakamichi dual capstan cassette decks.
This is a time consuming job though as thin tape twists, turns and crinkles up very easily needing careful tension, customised winding systems and protection from contaminants such as dust, grease, etc that could cause more damage to an already compromised recording.
High resolution audio and video digital tape conversions can use large amounts of computer storage. 8 bit uncompressed Standard Definition (SD) PAL video runs at 70 GB per hour and 24 bit 96 kHz audio files at 2 GB per hour.
As a result of this many of our analogue to digital tape transfers require the use of external storage, usually USB 2.0 portable hard drives, to supply the copied digital transfers back to the customer. Some drives supplied by customers have not been of great quality and not designed to be sent about in the post. One such drive we had recently, a Sony Vaio branded 2.5″ USB drive wouldn’t copy certain directories of important files with the Mac OS Finder or the Windows Explorer. While most of the drive copied this certain folder always resulted in a crashed computer!
Thanks to GNU/Linux we have a bit more power and information at our disposal about hard drives and IDE or USB interfaces. It’s always best practice to copy as much information from the drive or mirror it before attempting any other types of data recovery or file system repair. Using the standard dd
We’ve been honored recently to have won a large contract to help in the digital migration of an extensive educational video archive by the transfer from U-matic archive copies to uncompressed video files.
While the archive had been stored in an suitable environment and rarely if at all played, they had not survived well. The Sony branded tapes from the 1970s and 1980s all exhibited binder hydrolysis or sticky shed syndrome. We were still able to get good transfers though using our range of U-matic machines, particularly the Sony BVU-950P and For-A Time Base Corrector.
Greatbear recently helped the Streetscene section of Bristol City Council in an investigation in a serial flytipper.
DVD footage of the flytipper had been taken by a member of the public of flytipping activity but this DVD had other unrelated footage on that needed removal. The DVD was also damaged and needed slow, repeated reading to rip the MPEG stream successfully.
Using MPEGstreamclip it was then straightforward to trim the stream, resave and create a new DVD with just the necessary footage.
