[spectre] (fwd) Preservation of video: Obsolescence-rating of Video Tapes

[Andreas Broeckmann]

[this is a very informative piece about the important issue of the
preservation of our media cultural heritage; ab]



From: "Torben Soeborg" <soeborg@inet.uni2.dk>
To: <soeborg@inet.uni2.dk>
Subject: VIDEO ART\e-monitor no. 9
Date: Thu, 7 Mar 2002 22:51:48 +0100


THE DANISH VIDEO ART DATA BANK 

March 11, 2002
<...snip...>


2. Preservation of video: Obsolescence-rating of Video Tapes

How long is the life of a video tape? You ll find all kinds of estimates
from 5 to 20 years or more? Based on recent studies the American National
Media Laboratory indicates that magnetic tapes has a life expectancy of 10
to 30 years It depends of course on many things: the care and handling,
storage conditions and standards, the recording and playback machinery, the
format and type and the quality of the tape and the tape manufacturer. I
think that many of us has experiences about very old low band U-matic tapes
that still are in perfect shape and quite new VHS-tapes that already are
problematic.

But even if the tape is in good condition you might not be ale to screen it
because the playback machines are obsolete.

The American conservator Paul Messier from Boston Art Conservation has
(together with Sarah Stauderman) published a  Video Format Identification
Guide  on the Internet
(<http://www.video-id.com/>http://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
<http://www.montevideo.nl/>Montevideo/TBA (see
<http://www.videoart.suite.dk/e-monitor>VIDEO ART\e-monitor No. 2 and 3)
and the American <http://www.bavc.org/>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 (and Betacam SP) 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 surveys 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)


Strategies and Recommendations


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.


In the next VIDEO ART\e-monitor we will try to look at possible strategies
and recommendations for preventive maintenance, disaster recovery,
remastering and restoration.

----------------------------------------------

THE DANISH VIDEO ART DATA BANK is a non-profit agency for promoting Danish
video art outside Denmark

The VIDEO ART\e-monitor is an e-mail edition of the former printed
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