U-matic

Mouldy Tape

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.

In the case of narrow and thin tapes like DAT, this can be catastrophic.

opened up DAT cassette shell with white powdery mould on upper surface of tape wound around red plastic spool

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

What can we do to help?

We have a lot of experience treating tapes suffering from mould infestation and getting great results!

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.

Posted by greatbear in audio tape, video tape, 8 comments

SONY’s U-matic video cassette

Introduced by SONY in 1971 U-matic was, according to Jeff Martin, 'the first truly successful videocassette format'.

Philips’ N-1500 video format dominated the domestic video tape market in the 1970s. By 1974 U-matic was widely adopted in industrial and institutional settings. The format also performed a key role in the development of Electronic News Gathering. This was due to its portability, cost effectiveness and rapid integration into programme workflow. Compared with 16mm film U-matic had many strengths.

The design of the U-matic case mimicked a hardback book. Mechanical properties were modelled on the audio cassette's twin spool system.

Like the Philips compact audio cassette developed in the early 1960s, U-matic was a self-contained video playback system. This required minimal technical skill and knowledge to operate.

There was no need to manually lace the video tape through the transport, or even rewind before ejection like SONY's open reel video tape formats, EIAJ 1/2" and 1" Type C. Stopping and starting the tape was immediate, transferring different tapes quick and easy. U-matic ushered in a new era of efficiency and precision in video tape technology.

Mobile news-gathering on U-matic video tape

Emphasising technical quality and user-friendliness was key to marketing U-matic video tape.

As SONY's product brochure states, 'it is no use developing a TV system based on highly sophisticated knowledge if it requires equally sophisticated knowledge to be used'.

'The 'ease of operation' is demonstrated in publicity brochures in a series of images. These guide the prospective user through tape machine interface. The human operator, insulated from the complex mechanical principles making the machine tick only needs to know a few things: how to feed content and direct pre-programmed functions such as play, record, fast forward, rewind and stop.

New Applications

Marketing material for audio visual technology often helps the potential buyer imagine possible applications. This is especially true when a technology is new.

For SONY’s U-matic video tape it was the ‘very flexibility of the system’ that was emphasised. The brochure recounts a story of an oil tanker crew stationed in the middle of the Atlantic.

After they watch a football match the oil workers sit back and enjoy a new health and safety video. ‘More inclined to take the information from a television set,’ U-matic is presented as a novel way to combine leisure and work.

Ultimately ‘the obligation for the application of the SONY U-matic videocassette system lies with the user…the equipment literally speaks for itself.’

International Video Networks

Before the internet arrived, SONY believed video tape was the media to connect global businesses.

'Ford, ICI, Hambro Life, IBM, JCB...what do these companies have in common, apart from their obvious success? Each of these companies, together with many more, have accepted and installed a new degree of communications technology, the U-matic videocassette system. They need international communication capability. Training, information, product briefs, engineering techniques, sales plans…all can be communicated clearly, effectively by means of television'.

SONY heralded videotape's capacity to reach 'any part of the world...a world already revolutionised by television.' Video tape distributed messages in 'words and pictures'. It enabled simultaneous transmission and connected people in locations as 'wide as the world's postal networks.' With appropriate equipment interoperability between different regional video standards - PAL, NTSC and SECAM - was possible.

Video was imagined as a powerful virtual presence serving international business communities. It was a practical money-saving device and effective way to foster inter-cultural communication: 'Why bring 50 salesmen from the field into Head Office, losing valuable working time when their briefing could be sent through the post?'

Preserving U-Matic Video Tape

According the Preservation Self-Assessment Program, U-matic video tape ‘should be considered at high preservation risk’ due to media and hardware obsolescence. A lot of material was recorded on the U-matic format, especially in media and news-gathering contexts. In the long term there is likely to be more tape than working machines.

Despite these important concerns, at Greatbear we find U-matic a comparatively resilient format. Part of the reason for this is the ¾” tape width and the presence of guard bands that are part of the U-matic video signal. Guard bands were used on U-matic to prevent interference or ‘cross-talk’ between the recorded tracks.

In early video tape design guard bands were seen as a waste of tape. Slant azimuth technology, a technique which enabled stripes to be recorded next to each other, was integrated into later formats such as Betamax and VHS. As video tape evolved it became a whole lot thinner.

In a preservation context thinner tape can pose problems. If tape surface is damaged and there is limited tape it is harder to read a signal during playback. In the case of digital tape, damage on a smaller surface can result in catastrophic signal loss. Analogue formats such as U-matic, often fare better, regardless of age.

Paradoxically it would seem that the presence of guard bands insulates the recorded signal from total degradation: because there is more tape there is a greater margin of error to transfer the recorded signal.

Like other formats, such as the SONY EIAJ, certain brands of U-matic tape can pose problems. Early SONY, Ampex and Kodak branded tape may need dehydration treatment ('baked') to prevent shedding during playback. If baking is not appropriate, we tend to digitise in multiple passes, allowing us to frequently intervene to clean the video heads of potentially clogging material. If your U-matic tape smells of wax crayons this is a big indication there are issues. The wax crayon smell seems only to affect SONY branded tape.

Concerns about hardware obsolescence should of course be taken seriously. Early 'top loading' U-matic machines are fairly unusable now.

Mechanical and electronic reliability for 'front loading' U-matic machines such as the BVU-950 remains high. The durability of U-matic machines becomes even more impressive when contrasted with newer machines such as the DVC Pro, Digicam and Digibeta. These tend to suffer relatively frequent capacitor failure.

Later digital video tape formats also use surface-mounted custom-integrated circuits. These are harder to repair at component level. Through-hole technology, used in the circuitry of U-matic machines, make it easier to refurbish parts that are no longer working.

 

Transferring your U-matic Collections

U-matic made video cassette a core part of many industries. Flexible and functional, its popularity endured until the 1990s.

Greatbear has a significant suite of working NTSC/ PAL/ SECAM U-matic machines and spare parts.

Get in touch by email or phone to discuss transferring your collection.

Through-hole technology

Posted by debra in digitisation expertise, video tape, video technology, machines, equipment, 0 comments

Motobirds U-matic NTSC transfer


Motobirds, a 1970s all-girl motorbike stunt team from Leicester, have recently re-captured the public imagination.

The group re-united for an appearance on BBC One’s The One Show which aired on 1 April 2016. They hadn’t seen each other for forty years.

The Motobirds travelled all over the UK and Europe, did shows with the Original American Hell Drivers in Denmark, Sweden, Norway, Iceland, etc. We were originally four, then six, then fourteen girls.

We performed motorbike stunts, car stunts and precision driving, and human cannon. We were eventually followed by the Auto Angels, an all girl group from Devon or Cornwall. I don’t know of any other all girl teams’, remembers founding member Mary Weston-Webb.

Motobirds were notoriously daring, and wore little or no protective clothing.

The BBC article offers this sobering assessment: ‘most of the women’s stunts would horrify modern health and safety experts’.

We were pretty overjoyed in the Greatbear studio when Mary Weston-Webb, the driving force behind the recent reunion, sent us a NTSC uMatic video tape to transfer.

The video, which was in a perfect, playable condition, is a document of Motobirds strutting their stuff in Japan.

As Mary explains:

‘We (Liz Hammersley and Mary Connors) went to Japan with Joe Weston-Webb (who I later married) who ran the Motobirds for a Japanese TV programme called Pink Shock, as it was very unusual at that time, mid seventies, for girls to ride motorbikes in Japan. It was filmed on an island and we rehearsed and should have been filmed on the beach, which gave us plenty of room for a run up to the jumps. The day of the shoot, there had been a storm and the beach was flooded and we moved onto the car park of a shopping mall. Run up was difficult, avoiding shoppers with trolleys, round the flower beds, down the kerb, and a short stopping distance before the main road.’

Enjoy these spectacular jumps!

Thank you Mary for telling us the story behind the tapes.

http://www.bbc.co.uk/programmes/p03pr0q9/player

Posted by debra in video tape, 0 comments

Red Beat: U-matic Low Band Transfer and Video Synthesizers

The latest eclectic piece of music history to be processed in the Greatbear Studio is a U-matic Low Band video of ‘Dream/Dream Dub’ by Red Beat, a post-punk band that was active in the late 1970s and early 1980s. Despite emitting a strong wax crayon-like odour that is often a sure sign of a degraded U-matic tape, there were no issues with the transfer.

Red Beat formed in High Wycombe in 1978. After building up in solid fan base in the Home Counties they moved to London to pursue their musical ambitions. In London they recorded an EP that was released on Indie label Malicious Damage and did what most do it yourself punk bands would have killed to do: record a John Peel session. They also supported bands such as U2, Killing Joke, Thompson Twins and Aswad.

Originally inspired by New Wave acts such as Blondie and XTC, their later sound was more experimental, influenced by bands like PiL, Siouxsie and the Banshees and Killing Joke.

Roy Jones, singer and driving force behind getting Red Beat’s archive digitised explains that ‘we wrote together by jamming for hours till something sparked.’ Later evolutions of the band had more of a ‘pop orientation’ underscored by ‘a dark sound that fused Punk and Reggae and Tribal Beats.’ Songs by the band include the sci-fi inspired ‘Visit to Earth’ , ‘Ritual Sacrifice,’ a lamentation on the futility of war and ‘Searching for Change’, which explores the need for personal, spiritual and political transformation.

Video Synthesizers

In 1982 Red Beat formed their own indie label, Manic Machine Products, and released two further singles ‘See/Survival’ and ‘Dream/Dream Dub’, both distributed by Rough Trade.

The video of ‘Dream/ Dream Dub’ is the only existing video footage of the band at the time.

Roy’s motivation for sending it to Greatbear was to get the best quality transfer that he will then remaster, add a clean sound track to and upload to the Red Beat youtube playlist.

Of particular interest is ‘Dream/ Dream Dub’s use of video synthesizer footage which was, Roy tells me, ‘quite unique at the time. This footage was then edited with two tape analogue technology which is slow and not as accurate as modern editing.’

As Tom DeWitt explains ‘technically, the video synthesizer is more complex than its audio cousin. Video signals cover a frequency spectrum 100 times greater than audio and must be constructed according to a precise timing synchronization which does not exist in the one dimensional audio signal.’

In the early 1960s and 1970s, synthesizing video images was an emergent form of video art. Artists Shuya Abe and Nam June Paik created one of the first ‘video devices intended to distort and transform the conventional video image.’ [1] Part of their aim was to challenge the complacent viewer’s trans-fixation on the TV screen.

In the 1970s the artistic palette of the video synthesizer evolved. Bill Hearn was instrumental in developing ‘colorisation’ in 1972, and in 1975, Peter Sachs Collopy tells us, he incorporated this tool into ‘a full-featured synthesizer, the Videolab, which also produced effects like switching, fades, dissolves, wipes, and chromakey.’ [2]

‘Colourisation’ is a big feature of the Red Beat video. It refers to the ability to change the appearance of colours by mixing either the red, blue and green elements or the video colour parameters: luminance, chrominance and hue. In ‘Dream/ Dream Dub’ the red, green and blue colourisation is applied, accentuating the primary colours to give the image a garish, radioactive and extra-terrestrial quality.

Want more Red Beat?

If this article has sparked your curiosity about Red Beat you can buy their albums Endless Waiting Game and The Wheel from itunes.

The final word about the band must go to Roy: ‘We were part of a vibrant music scene. Other people enjoyed more success than us but we had a great time and created some great memories. I don’t think many people would remember our music but there are a few who buy our albums and remember seeing us live. We created our own bit of rock’n roll history and it’s worth documenting.’ [3]

Notes

[1] Chris Meigh-Andrews, A History of Video Art (London: Bloomsbury, 2013), 136.

[2] Peter Sachs Collopy ‘Video Synthesizers: From Analog Computing to Digital Art,’ IEEE Annals of the History of Computing, 2014, 74-86, 79.

[2] Thank you to Roy for generously sharing his memories of Red Beat and to Peter Sachs Collopy for sharing his research.

Posted by debra in video tape, video technology, machines, equipment, 0 comments

Videokunstarkivet’s Mouldy U-matic Video Tapes

Last year we featured the pioneering Norwegian Videokunstarkivet (Video Art Archive) on the Greatbear tape blog.

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 mouldy U-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.

The video tape being played back on vo9800 U-matic

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.

SONY BVU 950

The video tape being played back on SONY BVU 950

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.

Yet the quality of the playback we managed to achieve also underlines how a signal can be retrieved, even from the most mould-mangled analogue tapes. The same cannot be said of digital video and audio, which of course is subject to catastrophic signal loss under similar conditions.

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.

Posted by debra in audio / video heritage, digitisation expertise, video tape, 2 comments

Mistress or master? Digitising the cultural heritage of women’s movements

The Women’s Liberation Movement (WLM) is full of quirky examples of how womyn tried to wrestle culture from the sordid grip of male domination.

Part of this process was reinventing the world in wimmin’s image, word and song; to create and reclaim a lasting herstory in which sisterhood could flourish.

A recent U-Matic video tape transfer conducted in the Greatbear studio offers a window into this cultural heritage. 

State Your Destination was a film made by Bristol-based ’80s feminist film collective Women in Moving Pictures (W.I.M.P.S.), whose complete archive is stored at the Feminist Archive South.

We previously migrated another film by W.I.M.P.S called In Our Own Time, screened at the recent Translation/ Transmission Women’s Film Season which took place at Watershed.

The way women shirked the language of patriarchy is evident on the tape box. We digitised the ‘MISTRESS’ copy, not the master copy.

Seeing the mistress copy today is a reminder of the way gendered language influences how we can think about cultural forms.  The master copy, of course, in conventional understanding, is the finished article, the final cut. The master of the house – the person in charge – is gendered male. Yet is this still the case?

Writing about a similar issue almost thirty years later, sound theorists Jonathan Sterne and Tara Rodgers seem to think so:

‘If we find that audio-technical discourse renders signal processing in terms of masculinist languages of mastery and domination of nature, can we help but wonder after its broader social implications? Does it not also suggest a gendered set of relations to these technologies? It is any wonder we still find the design, implementation, marketing, and use of audio-signal processing technologies to be male-dominated fields? [To change things] it will require fundamentally rethinking how we model, describe, interact, and sound with signal processing technologies’.

For feminist women who felt systematically excluded from certain kinds of cultural and economic activity, the gendering of language was an extension of violence they experienced because they were women.

Making the tape a MISTRESS may help rectify the problem, as does crossing out the very idea of a master copy.

Posted by debra in video tape, 0 comments

Digitising Low Band U-matic Video Tapes – The resurgence of Philip Jap, pop icon

Philip Jap came from a time when mime, dance, slapped bass lines, mascara and techno-dystopic anthems were staple parts of a successful popular music career. Cut from the same new wave goth cloth as Gary Numan, Human League and John Foxx, sporting mesmeric dance moves like a male Kate Bush, Jap lit up the early 1980s with performances on the David Essex Showcase, an audience participation talent show similar to today’s Britain’s Got Talent or Pop Idol. Jap went on to sign for Carlin Music Publishing and A&M Records, release an eponymous solo album and have a top 40 hit with ‘Save Us,’ a dramatic plea for liberation from an increasingly intrusive ‘mechanical world.’

Jap retains a modest yet loyal fanbase (The Philip Jap Army), and his recordings will soon be made available through his twitter site. Although he did not have runaway commercial chart success, Jap went on to have a successful career as a composer and arranger for TV series and commercials and is the co-founder of AUDIOfield, a music production company.

The Greatbear studio has been graced with Jap’s music this week because we have been migrating a collection of low-band U-matic videos that feature a number of TV appearances and promotional videos, including the 30 minute ‘special’ that was recorded for the BBC.  In similar fashion to our recent transfer of Manchester Oi! band State Victims, the tapes were found in an old suitcase in a barn!

Although the tapes were mostly in good condition, some of the tapes were recorded on early SONY brand and were suffering from low Radio Frequency (RF) levels. RF levels are the recorded levels that can be read off the tape itself. To get a good, clear picture it is essential that the RF levels are strong. According to the AV Artifact Atlas, RF deterioration can occur because of a ‘poorly made recording on broken or mis-calibrated machine/record heads, or the use of poor quality video tape stock.’ Low RF levels may also occur if ‘the source media itself has been exposed to a strong magnetic field (unshielded speakers, motors, high-voltage transformers, etc.)’.

When a tape is suffering from low RF levels there are not loads of things you can do to reverse the process. This is because the signal recorded on the tape has essentially faded over time, due to a bad initial recording, unsuitable storage conditions leading to de-magnetisation or sticky shed, or poor quality tape (such as AMPEX or SONY U-matic tapes, although not exclusively). It is possible however to modify the tracking, a calibration adjustment which ensures the spinning playback head is properly aligned with the helical scan signal written onto the video tape. Tracking changes the speed at which the tape moves past the tape heads, which although spinning during playback, remain stationary. It is not the answer of all low RF ills, however, because the signal on the tape itself has become weaker, even if the calibration adjustment helps the machine read the signal more effectively.

Thankfully the tapes play back well, which is pretty amazing given that the tapes are over 30 years old and were never meant to be archive copies in the first place. We have also had a pretty enjoyable time watching and listening to Philip Jap’s amazing music. It is definitely time for a revival!

Posted by debra in video tape, 2 comments

Early digital tape recordings on PCM/ U-matic and Betamax video tape

We are now used to living in a born-digital environment, but the transition from analogue to digital technologies did not happen overnight. In the late 1970s, early digital audio recordings were made possible by a hybrid analogue/digital system. It was composed by the humble transport and recording mechanisms of the video tape machine, and a not so humble PCM (pulse-code-modulation) digital processor. Together they created the first two-channel stereo digital recording system.

The first professional use digital processing machine, made by SONY, was the PCM 1600. It was introduced in 1978 and used a U-matic tape machine. Later models, the PCM 1610/ 1630, acted as the first standard for mastering audio CDs in the 1980s. SONY employee Toshitada Doi, whose impressive CV includes the development of the PCM adaptor, the Compact Disc and the CIRC error correction system, visited recording studios around the world in an effort to facilitate the professional adoption of PCM digital technologies. He was not however welcomed with open arms, as the SONY corp. website explains:

'Studio engineers were opposed to digital technology. They criticized digital technology on the grounds that it was more expensive than analogue technology and that it did not sound as soft or musical. Some people in the recording industry actually formed a group called MAD (Musicians Against Digital), and they declared their position to the Audio Engineering Society (AES).'

Several consumer/ semi-professional models were marketed by SONY in the 70s and 80s, starting with the PCM-1 (1977). In a retro-review of the PCM-F10 (1981), Dr Frederick J. Bashour explains that

'older model VCRs often worked better than newer ones since the digital signal, as seen by the VCR, was a monochrome pattern of bars and dots; the presence of modern colour tweaking and image compensation circuits often reduced the recording system's reliability and, if possible, were turned off.'

Why did the evolution of an emerging digital technology stand on the shoulders of what had, by 1981, become a relatively mature analogue technology? It all comes down to the issue of bandwidth. A high quality PCM audio recording required 1-1.5 MHz bandwidth, which is far greater than a conventional analogue audio signal (15-20KHz). While this bandwidth was beyond the scope of analogue recording technology of the time, video tape recorders did have the capacity to record signals with higher bandwidths.

If you have ever wondered where the 16 bit/ 44 Khz sampling standard for the CD came from, it was because in the early 1980s, when the CD standard was agreed, there was no other practical way of storing digital sound than by a PCM Converter & video recorder combination. As the wikipedia entry for the PCM adaptor explains, 'the sampling frequencies of 44.1 and 44.056 kHz were thus the result of a need for compatibility with the 25-frame (CCIR 625/50 countries) and 30-frame black and white (EIAN 525/60 countries) video formats used for audio storage at the time.' The sampling rate was adopted as the standard for CDs and, unlike many other things in our rapidly changing technological world, it hasn't changed since.

The fusion of digital and analogue technologies did not last long, and the introduction of DAT tapes in 1987 rendered the PCM digital converters/ video tape system largely obsolete. DAT recorders basically did the same job as PCM/ video but came in one, significantly smaller, machine. DAT machines had the added advantage of being able to accept multiple sampling rates (the standard 44.1 kHz, as well as 48kHz, and 32kHz, all at 16 bits per sample, and a special LP recording mode using 12 bits per sample at 32 kHz for extended recording time).

Problems with migrating early digital tape recordings

There will always be the risk with any kind of magnetic tape recordings that there won't be enough working tape machines to playback the material recorded on them in the future. As spare parts become harder to source, tapes with worn out transport mechanisms will simply become inoperable. We are not quite at this stage yet, and at Greatbear we have plenty of working U-matic, Betamax and VHS machines so don't worry too much! Machine obsolescence is however a real threat facing tape-based archives.

Such a problem comes into sharp relief when we consider the case of digital audio recordings made on analogue video tape machines. Audio recordings 'work' the tape transport in a far more vigorous fashion than your average domestic video tape user. It may be rewound and fast-forwarded more often, and in a professional environment may be in constant use, thus leading to greater wear and tear.

Those who chose to adopt digital early and made recordings on tape will have marvelled at the lovely clean recordings and the wonders of error correction technology. As a legacy format however, tape-based digital recordings are arguably more at risk than their analogue counterparts. They are doubly compromised by fragility of tape, and the particular problems that befall digital technologies when things go wrong.

'Edge damage' is very common in video tape and can happen when the tape transport becomes worn. This can alter the alignments of transport mechanism, leading it to move move up and down and crush the tape. As you can see in this photograph the edge of this tape has become damaged.

Because it is a digital recording, this has led to substantial problems with the transfer, namely that large sections of the recording simply 'drop out.' In instances such as these, where the tape itself has been damaged, analogue recordings on tape are infinitely more recoverable than digital ones. Dr W.C. John Van Bogart explains that

'even in instances of severe tape degradation, where sound or video quality is severely compromised by tape squealing or a high rate of dropouts, some portion of the original recording will still be perceptible. A digitally recorded tape will show little, if any, deterioration in quality up to the time of catastrophic failure when large sections of recorded information will be completely missing. None of the original material will be detectable in these missing sections.'

This risk of catastrophic, as opposed to gradual loss of information on tape based digital media, is what makes these recordings particularly fragile and at risk. What is particularly worrying about digital tape recordings is they may not show any external signs of damage until it is too late. We therefore encourage individuals, recording studios and memory institutions to assess the condition of their digital tape collections and take prompt action if the recorded information is valuable.

 The story of PCM digital processors and analogue tapes gives us a fascinating window into a time when we were not quite analogue, but not quite digital either, demonstrating how technologies co-evolve using the capacities of what is available in order to create something new.

For our PCM audio on video tape transfer services please follow this link: greatbear - PCM audio on video tape

Posted by debra in audio tape, digitisation expertise, 4 comments

Copying U-matic tape: digitise via dub connector or composite video?

Digitising legacy and obsolete video formats in essence is simple but the technical details make the process more complex. Experience and knowledge are therefore needed to make the most appropriate choices for the medium.

The U-matic video format usually had two types of video output, composite and a y/c type connector that Sony named ‘Dub’. Originally designed as a higher quality method to make analogue ‘dubs’, or for connections in an edit suite, the Dub connector offers a higher performance signal path for the video signal.

It would make sense to use the higher quality dub output when digitising U-matic tapes but here lies the problem. Firstly the connector uses the larger 7 pin y/c type connector that can be quite hard to find connectors for.

Secondly and most significantly, the chrominance subcarrier frequency is not the standard PAL  4.43Mhz but down converted by U-matic recorders to 0.686Mhz for low band recordings and 0.984Mhz for high band recordings.

What this means in practice is that you’ll only get a monochrome image using the U-matic dub connector unless you can find a way to convert the chroma subcarrier frequency back to 4.43Mhz.

There are several solutions:

  1. Convert this Dub signal chroma frequency using one of a few older Timebase Correctors / Frame Synchronisers  from the U-matic era.
    These are now rare and often have other other faults that would degrade the signal.
  2. Take the Luma and Chroma signals at the correct frequency directly from certain test points on the circuit boards inside the machines.
    This can work well but is a slightly ‘messy’ solution and makes it hard to swap machines around, which is a necessity with older hardware.
  3. Convert the dub signal using a dedicated external dub – y/c converter circuit.
    This is our preferred solution that works well technically. It is flexible enough to swap around to different machines easily. It is also a relatively simple circuit that is easy to repair and doesn’t subject the video signal to  unnecessary extra processing.

Below are two stills taken from a Apple ProRes recording from a Low Band PAL U-matic tape.
The first image is via the Dub connecter but converted to PAL Y/C.
The second images is via the Composite video out.

 

It’s clear from the images that there is more fine detail in the picture from the U-matic Dub version. The pattern / texture in the jacket and the texture and tone in the face is more detailed.  In contrast, the version digitised through the Composite video connector has less noise but due to the extra encoding and decoding there is less detail and more ‘blurring’.

While less noise may be preferable in some instances, having the option to choose between these two is always better. It’s this kind of attention detail and investment in equipment and knowledge that we are proud of and makes us a preferred supplier of digitising services for U-matic video tape.

Posted by greatbear in digitisation expertise, video tape, 12 comments

Digitising Ampex U-matic KCS-20 Video Tapes

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.

Posted by debra in video tape, 2 comments

Digitising U-matic tape: Diagnosing & Treatment

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).

Walking Crusher at Foster Yeoman Ltd’s Torr Works in 1985 from Quarry Faces on Vimeo.

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.

Posted by debra in video tape, 0 comments

U-matic transfer and video preservation of Bristol reggae band Black Roots

2 U-matic video tapes were discovered of a Black Roots live performance in Bristol in the 1980s. We were able to restore, digitise and make the umatic transfer of this recording as a high quality, uncompressed Quicktime file then encode and author a DVD for future release by Bristol Archive Records.

Some information supplied by the label:

Black Roots were Bristol’s premier Reggae band throughout the eighties and having gone their separate ways in the nineties they reformed last year and will be rekindling the magic with an intimate hometown gig at the Fleece on Friday September 9th, the show coincides with the release of “Black Roots – The Reggae Singles Anthology”, released on Bristol Archive Records in collaboration with Nubian Records, this release showcases all of the band’s singles released during their first decade and as an extra bonus the CD issue comes coupled with a DVD of the band’s 1986 video release “Celebration” recorded at the long gone Studio nightclub in Bristol. This show will be something special and likely sell out so book your tickets early and don’t miss out.

thefleece.co.uk

Posted by greatbear in video tape, 0 comments

NTSC U-matic transfer of The Members – Solitary Confinement


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.

Posted by greatbear in video tape, 0 comments

U-matic transfer to DVD, Uncompressed Quicktime and Digi Beta

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.

Posted by greatbear in video tape, 12 comments