Great Bear Studio Visit – Archive for Mathematical Sciences and Philosophy

July 16th, 2013

This week in the Great Bear Studio we are being visited by Michael Wright, Director of The Archive for Mathematical Sciences and Philosophy.

The Archive for Mathematical Sciences and Philosophy holds an extensive collection of audio and video recordings on subjects in mathematics, physics and philosophy, particularly the philosophy and foundations of mathematics and the exact sciences recorded since the early 1970s.

The website explains further the rationale for collecting the recordings:

Such recordings allow historians of science and mathematics to form a better appreciation of the background to the emergence of new ideas; and also of the complex pattern formed by “roads not taken” – ideas which for whatever reason were laid aside, or apparently subsumed in other developments. Those ideas may later re-emerge in ways yielding a new perspective on those developments. Such a rich archive of primary oral source material naturally aids historical study of the Sciences and the conceptual and philosophical questions to which they give rise.

 The project started in 1973 when Michael recorded lectures, seminars and courses relating to Maths and Philosophy when he was a doctoral student. The early recordings were made in Oxford, London and Cambridge and were done on an enthusiastic, if amateur basis. In the 1980s and 1990s the recording process became more systematic, and more video recordings were taken. The archive is still collecting material, and Michael often travels to conferences and lectures to record contemporary debates in the field, as he is this week when he travels to Warsaw for Samuel Eilenberg Centenary conference (there are recordings of Eilenberg’s lectures and an interview collected in the archive).

Michael Wright in the studio.

What started as a hobby for Michael has now become a full time commitment. The archive contains a staggering 37,000 recordings, those he made and ones solicited from other individuals. They include recordings of figures such as Imre Lakatos, Ilya Prigogine, contemporary philosopher Alain Badiou and many more.

The majority of recordings from 1973-2003 were recorded on audio cassette format, although some were done on reel-to-reel recorders. Many of these recordings remain on analogue tape, and the biggest challenge for the archive is now to find the funds to migrate several thousand hours of recordings to digital format.

The archive also track downs and publishes existing material that may be collected in other archives, or are stored in people’s personal collections. For Michael the biggest revelation in constructing the archive was finding out about the amount of material people have that are sitting in the back of their cupboards. This is either because people have forgotten they exist, or because they simply do not known what to do with them.

The archive became a charitable trust in 2008 and names among its trustees English mathematical physicist and philosopher Sir Roger Penrose, and Martin Rees, former Master of Trinity College and Emeritus Professor of Cosmology at the University of Cambridge and President of the Royal Society.

Its an exciting, and transitional, time for the archive as it plans to take its next steps. In the coming years there are plans to develop the website through uploading ‘born digital’ information, attain funds for wholesale digitisation of tape and paper resources and continue to collect recordings. This ambitious project is well on its way to becoming a vital and unique contribution to the subject, and will interest many other people who are simply curious about these rich and complex topics.

 

How sustainable is digitisation?

July 8th, 2013

Often when we think about the reasons to digitise magnetic tape collections we are considering the future. We digitise to make material accessible so it can be used again, or to preserve it so subsequent generations can benefit or learn from it. But how sustainable is digitisation and digital technology? What is the ecological impact of the widespread and breathtakingly fast adoption of digital technologies since the late 1990s?

At an everyday, consumer level, the use of digital technologies comes with real human and environmental costs, as Professor Toby Miller and Professor Richard Maxwell demonstrate in a recent article in The Guardian. They argue that the very metaphors we use to describe digital media – ‘virtual,’ ‘cloud’, ‘streams’ and ‘mobiles’ – dangerously obscure the fact they come from materials, such as the minerals Tatalun, Tungsten, Tin and Gold, and cover up the exploitative labour conditions, and war torn situations from which they are extracted:

‘Suggestions that we live in a dematerialised world are not only exaggerated; they are doing more harm than good. One person’s cloud is another’s pollution, and one person’s mobile is another’s enslavement. From electronic waste to conflict minerals, the new media leave an indelible mark on bodies and the Earth they inhabit.’

The extent of violence and exploitation that lie at the end of the digital supply chain is hardly a secret. At a consumer level there seems to be very little resistance to the use of mobile digital devices, probably because our very social existence is dependent upon them in a culture where media is pervasive. It is not easy to opt out, and what would you do if you did?

1000s of circuit boards in a pile

As heavy users of digital technologies we walk with our heads in the clouds, so to speak, unable to access the wider environmental impact of our actions. This impact is intensified by the pressure to continually upgrade our devices, as Dr Chris Priest writes,

‘the regularity with which you replace a device becomes more important in determining the overall footprint of the device. If we take a hypothetical device with a 50% use footprint, and replace it after two years rather than three, then it will increase our overall footprint by 25%. Of course, new devices might be becoming increasingly efficient and this could offset the increase to some extent. Though even if the new device used no power, it could not offset it completely.’

Yet these are speculations not empirical fact. It is hard to know concretely what the environmental consequences of becoming immediate adopters of the latest (fastest, smallest, bestest) digital technologies are. One thing is certain, new goods will appear and people will be told they can’t live without them. This is how an economy driven by innovation works.

Thinking about the uptake of digital technologies at an institutional level, it is clear that within a technological climate pre-disposed to the production of ‘digital waste’ and obsolescence, the mismanagement of energy resources in order to keep digital data ‘alive’ (that is useable, accessible) is a real possibility. One only need turn to the financial and technological waste produced from the BBC’s Digital Media Initiative (DMI) to confirm that the creation of technical systems devised to manage large digital archives are not moving at the same relentless speed as the neoliberal market.

Which begs the question: can there be an ecological solution to the problem of digitisation, and the use of digital technologies in an innovation/ obsolescence economy? Can digitisation ever be energy efficient, non-exploitative and flexible enough to cope with the technological changes that will inevitably happen? What would a sustainable and ethical approach to digital information management look like?

As our world gets increasingly networked these are pressing questions effecting everyone. And clearly understanding the wider impact of the use of technology on people and the earth is a serious issue, usually forgotten when scrolling through data feeds in a voracious, but often distracted, manner. These are admittedly big questions and we welcome comments, links and ideas on how to answer them.

As keen hoarders of mechanical waste from the analogue era who are passionate about making data accessible in digital form, we are contributing to a world that places unprecedented value on technological information.

Need this, however, always be at the expense of people and the world we share as currently it seems to be?

 

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

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.

Panasonic VTR NV-8030 transferring a tape

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

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.

Diagram of a  Panasonic VTR NV-8030

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?

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.

Two reel to reel plastic spools and tape box

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.

Inside of U matic tape machine with label 'do not touch the tape inside'

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.

leads and cables

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.

copy umatic tape, digitise via dub connector or composite video?

July 1st, 2013

umatic dub to y/c converter detail

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 umatic 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 umatic 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 umatic 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 umatic 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 umatic 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.

kieran prendiville umatic screenshot dub connector

 

kieran prendiville umatic screenshot composite video connector

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 umatic video tape.

4 track 1/4 inch reel to reel tape recorded in mono – The Couriers Folk Club, Leicester

July 1st, 2013

We were recently sent a ¼ inch tape by Ed Bates that included recordings from the Couriers Folk Club in Leicester,  which ran from Autumn 1964 – June 1974.

The tape features performances from The Couriers (Jack Harris and Rex Brisland), George and Thadeus Kaye, Bill Pickering, Mark Newman and Mick Odam.

Jack Harris, who alongside Rex Brisland ran the club, describes how ‘traditional singers like Bert Lloyd, Ewan MacColl and Pete Seeger, Bob Davenport were regular visitors together with ageing ploughboys, miners and fishermen who were often so infirm or unlikely to make their own way to Leicester they had to be fetched by car.’

As well as supporting grassroots folk music from the local area, well known performers such as musical superstar Barbara Dickson, Paul Simon and Joni Mitchell graced the stage.

Inside of tape box, The Couriers live at the Couriers Folk Club Whyte Swan 6.8.66.

The tape recordings we received span five years. The first recording was made on 6 August 1966, then 3 September 1966, 8 February 1970 and finally 9 April 1971.

Each performance was recorded on a separate track in mono. This means that the 7” long spool contains 8 hours of music!

Like today’s MP3 digital files, the quality of the recorded sound is compromised because so much information is squeezed into a smaller space on the tape. A better quality recording would have been made if all four channels were used for a single performance, rather than one track for each performance.

The speed at which recordings were made also effects the quality of the recordings, simply because you can record more information per second at a faster rate. The tapes we were sent were recorded at 7 ½ per second on what is likely to have been a domestic tape recorder such as the Sony TC-263D. Ed’s letter to us speaks volumes about the conditions in which the recordings were made:

‘I was present at the Couriers Folk Club in Leicester when they were recorded so I can say that the recording quality is not good. The Sony recorder was used as an amplifier and on some occasions (if someone remembered) a tape was recorded.’

While the recordings certainly would have benefited from less haphazard recording conditions, the quality of the transfer is surprisingly crisp, as you can hear from this excerpt.

Excerpt from the digitised recordings of the Couriers folk club

The tape was in good condition, as Philips magnetic reel-to-reel tape often survives well over time, which aided a good transfer. One thing we were especially attentive to in the transfer process was carefully adjusting the azimuth, because of the slow speed of the original recording and the narrow track width.

Diagram of how to record on magnetic tape using a 4 track recorder, demonstrating a 1/4 inch tape divided into four lines on which each track can be recorded

Image taken from the BASF magnetic tape manual that  illustrates  how  four tracks can be recorded on magnetic tape

The emergence of recordings of the Couriers Club is especially timely given the recent launch of the English and Folk Dance Society‘s The Full English online digital archive . This contains a massive 44,000 records and over 58,000 digitised images about English folk history.

With a dozen or more tapes recently found from the Club, we look forward to helping this unique part of cultural heritage become accessible again.

Digital Preservation – Planning for the Long Term

June 26th, 2013

There are plenty of reflections on the Great Bear tape blog about the fragility of digital data, and the need to think about digitisation as part of a wider process of data migration your information will need to make in its lifetime.

We have also explored how fast moving technological change can sometimes compromise our capacity to construct long term strategies for the survival of digital data.

digital-data-stream-visualisation (2)

This why it is so important that organisations such as the Digital Preservation Coalition, founded in February 2002, articulate a vision that aims to make ‘digital memory accessible tomorrow.’ Their website goes on to say:

Our generation has invested as never before in digital resources and we’ve done so because of the opportunity they bring. They have grown in volume, complexity and importance to the point that our children are baffled by the inefficiencies of the analogue age. Pervasive, fluid and fragile: digital data is a defining feature of our age. Industry, commerce, government, law, research, health, social care, education, the creative industries, the heritage sector and private life depend on digital materials to satisfy ubiquitous information needs and expectations. Digital preservation is an issue which all organisations, particularly in the knowledge sector, will need to address sooner or later.

As providers of a digitisation service it is important for us to understand digitisation in line with the ideas articulated above. This means creating high quality, uncompressed files that will make it as easy as possible for data migrations to happen in the future should they need to.

Organisations such as the Digital Preservation Coalition are providing sensible advice and creating forums for learning and debate about the problems and possibilities of digital preservation.

These are two things that are needed as we come to navigate an information environment heavily populated by ‘pervasive, fluid and fragile’ digital data.

 

‘Mysterious little reddish-brown ribbon’: BASF Magnetic Recording Tape

June 26th, 2013

‘It seems we are living in an age in which practically every dream comes true. At no time in the past have so many scientific discoveries and inventions changed our way of life and the face of the world. Yes, we live in the age of science! Maybe we are forgetting to be awed, or are we so used to acquainting ourselves with the new that we seem to take anything for granted nowadays?’

This is the opening paragraph to A Comprehensive Booklet on BASF Magnetic Recording Tape, published c.1965 by the German company BASF.

Tape Book Cover

The booklet, that we will feature more of in later posts, offers advice and instructions on how to record sound on magnetic tape.

While in today’s culture we may well have forgotten ‘to be awed’ by sound recording technology, there was a time when home recording was an extremely novel activity. As our recent post about Brian Pimm-Smith’s tapes demonstrates, sound recording was done by enthusiasts – it was by no means an everyday activity.

Tape Book Insides 7

Tape recording clubs were however very popular in the 1960s-1970s, with groups forming all around the country.

Sound artist Mark Vernon describes how ‘dedicated amateurs would meet and swap tips, exchange recordings, enter competitions and arrange activities such as field recording trips. Eager members would lug heavy reel-to-reel recorders around the countryside, to church concerts, fire stations, airports and carnivals to capture the sounds around them.’

The excitement of recording sound on a ‘mysterious little reddish-brown ribbon’ is clear from reading the BASF manual. There is no shortage of awe for the ‘magic tape that practically does everything from writing out cheques to guiding missiles in space.’

In contemporary western culture the use of recording technologies has become as common as eating or breathing. Mystery and magic are words not often used to describe our laptops, phones or tablets. Yet it may well be worth remembering how mysterious and magic technology can be. That the things we take for granted as part of our everyday lives were once new inventions that radically transformed perceptions and our ability to document the world we live in.

As the BASF manual enthused, ‘the multitude of different impressions in the acoustic world…are just as beautiful and gratifying as those of the visible world [and] can now be conserved for all posterity.’

Repairing obsolete media – remembering how to fix things

June 17th, 2013

A recent news report on the BBC website about recycling and repairing ‘old’ technology resonates strongly with the work of Great Bear.

The story focused on the work of Restart Project, a charity organisation who are encouraging positive behavioural change by empowering people to use their electronics for longer. Their website states,

the time has come to move beyond the culture of incessant electronics upgrades and defeatism in the face of technical problems. We are preparing the ground for a future economy of maintenance and repair by reskilling, supporting repair entrepreneurs, and helping people of all walks of life to be more resilient.

We are all familiar with the pressure to adopt new technologies and throw away the old, but what are the consequences of living in such a disposable culture? The BBC report describes how ‘in developed nations people have lost the will to fix broken gadgets. A combination of convenience and cultural pressure leads people to buy new rather than repair.’

These tendencies have been theorised by French philosopher of technology Bernard Stiegler as the loss of knowledge of how to live (savoir-vivre). Here people lose not only basic skills (such as how to repair a broken electronic device), but are also increasingly reliant on the market apparatus to provide for them (for example, the latest new product when the ‘old’ one no longer works).

A lot of the work of Great Bear revolves around repairing consumer electronics from bygone eras. Our desks are awash with soldering irons, hot air rework stations, circuit boards, capacitors, automatic wire strippers and a whole host of other tools.

OLYMPUS DIGITAL CAMERA

We have bookshelves full of operating manuals. These can help us navigate the machinery in the absence of a skilled engineer who has been trained how to fix a MII, U-Matic or D3 tape machine.

As providers of a digitisation service we know that maintaining obsolete machines appropriate to the transfer is the only way we can access tape-based media. But the knowledge and skills of how to do so are rapidly disappearing – unless of course they are actively remembered through practice.

The Restart Project offers a community-orientated counterpoint to the erosion of skills and knowledge tacitly promoted by the current consumer culture. Promoting values of maintenance and repair opens up the possibility for sustainable, rather than throwaway, uses of technology.

Even if the Restart Project doesn’t catch on as widely as it deserves to, Great Bear will continue to collect, maintain and repair old equipment until the very last tape head on earth is worn down.

D1 digital video transfer – new additions and economies of size

June 10th, 2013

A recent addition to the greatear digitising studio is a BTS D1 digital video cassette recorder.

As revolutionary as it was at the time, early digital audio and video tape recording is more threatened with obsolescence than earlier analogue formats.

bts-dcr-300-d1-digital-video-recorder

Introduced in 1986, D-1 was the very first, real-time, digital broadcast-quality tape format. It stored uncompressed digitized component video, had uncompromising picture quality and used enormous bandwidth for its time. The maximum record time on a D-1 tape is 94 minutes.

Enormous is certainly the word for the D1 tape! Compared with the so-called ‘invisible’ nature of today’s digital data and the miniDV introduced in 1998, this tape from 1992 is in comedy proportions.

d1-minidv-tape-comparison-2

D-1 was notoriously expensive and the equipment required large infrastructure changes in facilities which upgraded to this digital recording format.

Early D-1 operations were plagued with difficulties, though the format quickly stabilized and is still renowned for its superb standard definition image quality, sometimes referred to as a ‘no compromise’ format.

D-1 kept the data recorded as uncompressed 8bit 4:2:2, unlike today where compression is required for digital data to save space and time for practical delivery to the home, but sacrificing the picture and sound quality in the process.

D1 was supplanted by subsequent D models that recorded a combination of component (D5) and composite (D3) signals.

Digitising Audio Tape – Process, Time & Cost

June 10th, 2013

Last week we wrote about the person time involved in transferring magnetic tape to digital files, and we want to tell you more about the processes involved in digitisation work.

While in theory the work of migrating media from one format to another can be simple, even the humble domestic cassette can take a substantial amount of time to transfer effectively.

Doing transfers quickly would potentially keep the costs of our work down, but there are substantial risks involved in mass migrations of tape-based material.

Problems with digital transfers can occur at two points: the quality of the playback machine and the quality of the tape.

First, lets focus on the playback machine.

Each time a cassette is transferred we have to ensure that the cassette deck is calibrated to the technical specification appropriate to that machine. Calibration is a testing procedure where a standard test tape is used to set the levels for tape to be digitised. The calibration process allows us to check tapes are played back at the correct speed and audio levels, that wow and flutter levels are set and the azimuth is aligned.

Azimuth refers to the angle between the tape head(s) and tape. Differences in Azimuth alignment arise from the azimuth of the original recording. You cannot know this information from just looking at a tape and you will get a sub-optimal transfer unless you adjust your machine’s azimuth to match the original recording.

sony-apr-5003-headblock-azimuth

Regularly checking the Wow and Flutter on the tape machine is also very important for doing quality transfers. Wow and flutter refer to fluctuations in speed on the playback mechanism, flutter being a higher rate version of wow. If you have listened to a tape you will probably be familiar with the sound of warped and woozy tape – this is the presence of wow. All tape machines have wow and flutter, but as components in the mechanisms stretch there is the potential for wow and flutter to increase. It is therefore essential to know what level the wow and flutter are set on your tape deck –less than 0.08% Weighted Peak on our Nakamichi 680 machines – to ensure optimal transfer quality.

Not all cassette machines were made equal either, and the quality of playback is absolutely dependent on the type of machine you have. There is a massive difference between the cheap domestic cassette machines made by Amstrad, to the cassette decks we use at Great Bear. Nakamichi machines were designed to squeeze the most out of the cassette, and their performance is way above the standard ‘two head’ cheap domestic machines.

Even with a Nakamichi deck, however, they have to be regularly checked because they are fragile electromagnetic machines that will drift out of specification over time. When machines drift they slip out of alignment, therefore effecting their operating capacity. This can occur through subtle knocks, everyday wear and tear and general ageing of mechanical and electrical components. For example, with extended use the grease in the components dries up and goes hard, and therefore affects the movement of the mechanisms.

Wow-and-flutter-monitor

Problems can also arise with the tapes themselves.

Most issues arise from tapes not being played back in well calibrated machines.

With audio cassettes the potential for azimuth error is increased because the speed the tape moves pasts the head is very slow. The tape therefore needs to be assessed to see if it is in a playable condition. It is played back in mono because it is easier to hear if there are problems with the azimuth, and then the azimuth is manually adjusted on the machine.

Migrating tape is unquestionably a ‘real time’ process. You need to listen and monitor what’s on the tape and the digitised version to ensure that problems with the transfer are detected as it is happening. It is a very hands on activity, that cannot be done without time, care and attention.

From digital files back to analogue tape

June 10th, 2013

The bread and butter work of Great Bear Analogue and Digital Media is to migrate analogue and digital magnetic tape to digital files, but recently we were asked by a customer to transfer a digital file to ¼ analogue tape.

The customer was concerned about the longevity of electronic digital formats, and wanted to transfer his most valued recordings to a tangible format he knew and trust. Transferring from digital to analogue was certainly more expensive: the blank tape media cost over £50 alone.

In a world where digital technology seems pervasive, remaining so attached to analogue media may appear surprising. Yet the resilience of tape as a recorded medium is far greater than is widely understood.

Take this collection of old tapes that are in the back yard of the Great Bear office. Fear not customers, this is not what happens to your tapes when you send them to us! They are a collection of test tapes that live outside all year round without shelter from the elements. We use them to test ways of treating degraded tapes because we don’t want to take unnecessary risks with our customer’s material.

audio-cassette-tapes-left-outside-for-years

Despite being subject to pretty harsh conditions, the majority of material on these tapes is recoverable to some degree.

Would digital data stored on a hard drive survive if it had to endure similar conditions? It is far less likely.

Due to its electronic composition digital data is fragile in comparison with analogue magnetic tape. This is also the ironic conclusion of Side by Side (2012), the documentary film narrated by Keanu Reeves which explores the impact of digital technology on the film industry.

Requests for digital to analogue transfers are fairly rare at Great Bear, but we are happy to do them should the need arise!

And don’t forget to back up your digital files in at least three different locations to ensure it is safe.

Real time transfers – digitising tape media

June 3rd, 2013

In theory the work we do at Great Bear is very simple: we migrate information from analogue or digital magnetic tape to electronic digital files.

Once transferred, digital files can be easily edited, tagged, accessed, shared or added to a database. Due to the ubiquitous nature of digital media today, if you want to use your data, it needs to be in a digital form.

In practice however, there are a lot more issues that arise when migrating tape based media. These can stem from the obsolescence of machines (spare parts being a particular issue), physical problems with the tape and significantly, the actual person-time involved in doing the transfer.

threading-eiaj-video-tape-closeup

While large institutions like the Library of Congress in USA can invest in technology that enables mass digitisation like those developed by Samma Systems, most transfers require operators to do the work. The simple truth is that for fragile and obsolete tape media, there is no other option. In the film ‘Living Archive – Preservation Challenge‘ David Crostwait from American digitisation company DC Video describes the importance of careful, real time transfers:

‘When a tape is played back, that tape starts from the very beginning and may run for 60-65 minutes straight. One person sits in front of that machine and watches that tape from beginning to end, s/he does nothing else but watch that tape. We feel this procedure is the only way to guarantee the highest quality possible.’

threadimg-eiaj-half-inch-video-tape

At Great Bear we echo this sentiment. We give each transfer individual attention so that the information is migrated accurately and effectively. Sometimes this means doing things slowly to ensure that tape is spooled correctly and the tension within the tape pack is even. If transfers are rushed there is always the danger that tape will get crumpled or damaged. As the saying goes, ‘the more haste, the worse speed’.

 

Archiving for the digital long term: information management and migration

June 3rd, 2013

As an archival process digitisation offers the promise of a dream: improved accessibility, preservation and storage.

However the digital age is not without its archival headaches. News of the BBC’s plans to abandon their Digital Media Initiative (DMI), which aimed to make the BBC media archive ‘tapeless’, clearly demonstrates this. As reported in The Guardian:

‘DMI has cost £98.4m, and was meant to bring £95.4m of benefits to the organisation by making all the corporation’s raw and edited video footage available to staff for re-editing and output. In 2007, when the project was conceived, making a single TV programme could require 70 individual video-handling processes; DMI was meant to halve that.’

The project’s failure has been explained by its size and ambition. Another telling reason was cited: the software and hardware used to deliver the project was developed for exclusive use by the BBC. In a statement BBC Director Tony Hall referred to the fast development of digital technology, stating that ‘off-the-shelf [editing] tools were now available that could do the same job “that simply didn’t exist five years ago”.’

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The fate of the DMI initiative should act as a sobering lesson for institutions, organisations and individuals who have not thought about digitisation as a long, rather than short term, archival solution.

As technology continues to ‘innovate’ at startling rate,  it is hard to predict how long the current archival standard for audio and audio-visual will last.

Being an early adopter of technology can be an attractive proposition: you are up to date with the latest ideas, flying the flag for the cutting edge. Yet new technology becomes old fast, and this potentially creates problems for accessing and managing information. The fragility of digital data comes to the fore, and the risk of investing all our archival dreams in exclusive technological formats as the BBC did, becomes far greater.

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In order for our data to survive we need to appreciate that we are living in what media theorist Jussi Parikka calls an ‘information management society.’ Digitisation has made it patently clear that information is dynamic rather than stored safely in static objects. Migrating tape based archives to digital files is one stage in a series of transitions material can potentially make in its lifetime.

Given the evolution of media and technology in the 20th and 21st centuries, it feels safe to speculate that new technologies will emerge to supplant uncompressed WAV and AIFF files, just as AAC has now become preferred to MP3 as a compressed audio format because it achieves better sound quality at similar bit rates.

Because of this at Great Bear we always migrate analogue and digital magnetic tape at the recommended archival standard, and provide customers with high quality and access copies. Furthermore, we strongly recommend to customers to back up archive quality files in at least three separate locations because it is highly likely data will need to be migrated again in the future.

Digitising Ampex U-Matic KCS-20 Video Tapes

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

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.


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