The American conservator Paul Messier from Boston Art Conservation has (together with Sarah Stauderman) published a “Video Format Identification Guide” on the Internet (www:video-id.com ) where he has listed almost all known video formats from 1956  to present (except for DV-formats) with obsolescence ratings for each format. I take the liberty to quote the rating scale from the web site:

Extinct: Only one or two playback machines may exist at specialist laboratories. The tape itself is more than 20 years old.

Critically endangered: There is a small population of ageing playback machinery, with no or little engineering or manufacturing support. Anecdotal evidence indicates that there are fewer working machine-hours than total population of tapes. Tapes may range in age from 40 years to 10 years.

Endangered: The machine population may be robust, but the manufacture of the machinery has stopped. Manufacturing support for the machines and the tapes becomes unavailable. The tapes are often less expensive, and more vulnerable to deterioration.

Threatened: The playback machines are available; however, either the tape format itself is unstable or has less integrity than other available formats, or it is known that a more popular or updated format will be replacing this one in a short period of time.

Vulnerable: This is a current but highly proprietary format.

Lower risk: This format will be in use over the next five years (1998-2002).

Of course Paul Messier points out that these ratings are subjective but based on sampling done within the United States. Based on his estimate many videotapes ought to undergo immediate preservation because they are passed their estimated life expectancy – and worth: passed the lifetime and availability of the required playback machinery. You not only have the problems with media degradation and format obsolescence but also with hardware obsolescence. Market demand for higher image quality, new features etc. drive manufactures toward constant innovation, leaving older formats and playback devices not only unsupported, but also without spare parts and scarcity of expertise to maintain and operate “vintage” playback machines. 

Looking at the ratings for the more recent formats it is interesting to see, that Sony Digital Betacam is rated as “vulnerable” and Betacam SP as “threatened” – interesting because both the Dutch Montevideo/TBA  and the American BAVC /Bay Area Video Coalition transfer older video formats to Digital Betacam as a preferred choice for preservation  - or to Betacam SP.

The reason for this is that they want to preserve all the information with as few changes as possible.  With Digital Betacam you best preserve the “originality” of the original video art work. Other digital techniques like DV and DVD inevitably by more or less degree of compression “destroys” the original analogue art work: You would not be able to “recreate” it in its original form because a compressed format means a loss of information, and thus a change in the original work.

Already now more and more video art works are recorded with digital camcorders and also edited with digital equipment. The final Master would be on a digital video format. The advantage is that copies of the original tape can be made without any loss of the original quality. A digital copy of a digital tape is or can be made that is truly identical to the original Master. This should in the future with obsolescence of analogue video equipment overcome the “originality-problem” described above.

So far so good. The problem is though when it comes to deterioration. With an analogue tape the deterioration over time is gradual and discernible and even with severe tape degradation some portions of the original recording will still be perceptible. A digitally recorded tape shows little, if any, deterioration in quality over time – up to the very time of a catastrophic failure when large sections of the recorded information will be completely missing – and none of the original material will be detectable in these missing sections.

If you want a really technical survey of different video recording formats (mainly the PAL versions) you should go to the web site:

 http://www.hut.fin/~iisakkil/videoformats.html

by Mika Iisakkila from Finland. He also survey the digital recording formats, both uncompressed and compressed. In his “Notes on specification and nomenclature” he also has an interesting note about “Broadcast quality defined – not!”   (a problem you as video artist using consumer equipment often get into – but “that is another story” as Hans Christian Andersen would say).

Many, especially small, video archives don’t have staff trained to deal with archival/maintenance/restoration issues and or lack resources to protect their holdings in any formal way – and individual artists, focusing on production, may have even less experience and knowledge of preservation efforts.