Posts Tagged ‘restoration’

Significant properties – technical challenges for digital preservation

Monday, April 28th, 2014

A consistent focus of our blog is the technical and theoretical issues that emerge in the world of digital preservation. For example, we have explored the challenges archivists face when they have to appraise collections in order to select what materials are kept, and what are thrown away. Such complex questions take on specific dimensions within the world of digital preservation.

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.

DSC04797 Significant properties   technical challenges for digital preservation

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 flutter after 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.

Climate Change, Tape Mould and Digital Preservation

Monday, March 31st, 2014

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.

DSC04439 Climate Change, Tape Mould and Digital Preservation

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.

EIAJ ½ inch Video Tape Transfers – Working with Community Groups to Develop Digitisation Projects

Monday, February 17th, 2014

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

DSC04127  EIAJ ½ inch Video Tape Transfers   Working with Community Groups to Develop Digitisation Projects 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.

Reel-to-Reel tape digitised of Manchester Oi! Band State Victims

Monday, February 17th, 2014

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.

DSC03992 Reel to Reel tape digitised of Manchester Oi! Band State Victims

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.

End of year thank yous to our customers

Monday, December 16th, 2013

What a year it has been in the life of Great Bear 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.

Throughout the year we have been transported to a breathtaking array of places and situations via the ‘mysterious little reddish-brown ribbon.’ Spoken word has featured heavily, with highlights including Brian Pimm-Smith‘s recordings of his drive across the Sahara desert, Pilot Officer Edwin Aldridge ‘Finn’ Haddock’s memories of World-War Two, and poet Paul Roche reading his translation of Sophocles’ Antigone.

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.

DSC03273 End of year thank yous to our customersOn 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.

Paul Roche recordings & preservation challenges with acetate reel-to-reel magnetic tape

Monday, November 25th, 2013

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.

IMAG0332 1024x707 Paul Roche recordings & preservation challenges with acetate reel to reel magnetic tapeWhen 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!

Digitising Shedding Magnetic Multi-track Tape & the history of John Peel favourites BOB

Wednesday, November 13th, 2013

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.’

8 Track Headshot 1 Digitising Shedding Magnetic Multi track Tape & the history of John Peel favourites BOB

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:

Shedder Digitising Shedding Magnetic Multi track Tape & the history of John Peel favourites BOB

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 A 80 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.

Studer A 80 Digitising Shedding Magnetic Multi track Tape & the history of John Peel favourites BOB

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.

Dirty Cloth Digitising Shedding Magnetic Multi track Tape & the history of John Peel favourites BOB

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 BOB by Richard Blackborow

RichardInBanwellStudio Digitising Shedding Magnetic Multi track Tape & the history of John Peel favourites BOB 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!

GroupShot MK1 Banwell Digitising Shedding Magnetic Multi track Tape & the history of John Peel favourites BOB

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.

This is a link to the video we made for the song back in 1989 in a freezing warehouse in Hull! It appeared on Kats Karavan – The History of John Peel on the Radio compilation that was released in 2009.

***

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!

A word about metadata and digital collections

Monday, September 23rd, 2013

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 many other features on this blog, 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.

schema A word about metadata and digital collections

Metadata can in fact be split into three kinds, as Ian Ireland writes in this article:

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.

Remembering Ray Dolby pioneer of analogue noise reduction

Monday, September 16th, 2013

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.

An obituary in The Guardian described how:

‘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.

Dolby A Rack Remembering Ray Dolby pioneer of analogue noise reduction

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.

Dolby SR Board Remembering Ray Dolby pioneer of analogue noise reduction

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.

Sony V62 EIAJ reel to reel video tape transfer for Barrie Hesketh

Monday, July 8th, 2013

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.

Panosonic VTR NV 8030 1024x800  Sony V62 EIAJ reel to reel video tape transfer for Barrie Hesketh

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.

Screenshot of the Audience Reactions 1024x821  Sony V62 EIAJ reel to reel video tape transfer for Barrie Hesketh

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 Great Bear Studio we have the National Panasonic Time Lapse VTR NV-8030 and Hitachi SV-640.

15  Sony V62 EIAJ reel to reel video tape transfer for Barrie Hesketh

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.

What is the future of analogue media?

Monday, July 1st, 2013

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.

DSC01263 1024x680 What is the future of analogue media?

We have written extensively on this blog about the problem of obsolescence, and how we collect machines and learn the skills to fix them.

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.

DSC01234 1024x680 What is the future of analogue media?

There is one analogue format that has flourished in the 21st century: vinyl.

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, as this article discusses.

DSC01326 1024x680 What is the future of analogue media?

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.

Digitising Ampex U-Matic KCS-20 Video Tapes

Wednesday, May 29th, 2013

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.

ampex umatic tapes dehydrating Digitising Ampex U Matic KCS 20 Video Tapes

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.

digitising tape issues

Friday, January 25th, 2013

The main work of Great Bear 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.

wire copy hand 858x1024 digitising tape issues

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.

digitising u-Matic tape: Diagnosing & Treatment

Friday, January 25th, 2013

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.

oven 300x200 digitising u Matic tape: Diagnosing & Treatment

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 Great Bear includes using our range of in-house test tapes, can the correct remedy be found.

Tape mould cleaned and removed. Rare lost masters recovered and preserved for Druidcrest Ltd

Friday, September 30th, 2011

IMAG0858 Tape mould cleaned and removed. Rare lost masters recovered and preserved for Druidcrest Ltd

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.

IMAG0829 Tape mould cleaned and removed. Rare lost masters recovered and preserved for Druidcrest Ltd

 

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 and 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.


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