[spectre] VIDEO ART\e-monitor Preservation of Video 2
Torben Soeborg
soeborg@inet.uni2.dk
Thu, 4 Apr 2002 12:35:11 +0200
VIDEO ART\e-monitor 10 =13 THE DANISH VIDEO ART DATA BANK
March 25, 2002
Content
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Preservation of Video Part 2: Preservation Issues
* Degradation Problems* * What can go wrong with Magnetic Tape?* * My
concern =13 right now!* * What can be done: Passsive and Active
Precautions*
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Preservation Issues: Degradation Problems
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Speaking of older tapes e.g. analogue recorded video tapes, you might ask:
What are the preservation issues?
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The answer is that it is a problem of media degradation and a double
problem of obsolescence: format obsolescence and hardware/machinery
obsolescence.
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Media degradation:
Because of the high data transfer rates demanded by video recording
magnetic tape has been the medium choice for video formats - at least up
to now/recently =13 but magnetic tape was never designed as a long-term
storage medium but primarily designed to be easy to record, easy to replay
and easy to copy. And the degradation is not only due to this inherent
instability of video tapes but also because magnetic tapes is not a stable
material at the most common ambient storage temperature and relative
humidity. If the tape is accessed /playbacked very often and on different
quality of playback devices it wear out the tape, but even in storage
unused tapes will decay over time.
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=46ormat obsolescence:
Surveys of videotape formats introduced since about 1955-56 list more than
60 different formats. Many of these formats are based on and are upgrading
of earlier formats but many was or are also new and different from earlier
formats Many of these formats had a very short life time and are now
obsolescence.
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Hardware/machinery obsolescence:
Even if the life of your older tapes are still in good conditions and even
if their life can be maximized, by good conservation and management
practice and by ideal storage conditions this is of no value if it outlives
the technology required to reproduce it: you might not be able to play them
because you might not be able any more to get hold in the playback
machinery needed for the old tape format. The hardware is not produced any
more and those old playback devises that still might exist are often poorly
maintained and therefor not able to give optimal playback. It is not only
difficult to get repair parts but there is also a scarcity of expertise
concerning how to maintain, repair and operate =1Cvintage =1D playback devi=
ces
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What can go wrong with Magnetic Tape?
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Grossly speaking you can talk about a) technical degradation, b)
degradation by handling, c) degradation by storage and d) degradation
through playback devices. The following outline is but just some of the
problems:
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a) =1CTechnical =1D degradation of tape:
- binder degradation
- lubricant loss
- magnetic particle instability
- tape backing/substrate deformation
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b) Degradation by handling of tape:
- dropping tape/cassette
- contamination by dirt, dust, fingerprints, food, cigarette
smoke, air pollution etc.
- not acclimatized to the playback environment
- exposed to sunlight, water or other types of fluid
- not rewinding tape after use
- frequently accessed and played
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c) Degradation by storage:
- storage on radiators, in windows, on top of TV/monitor, playback
machinery, magnetic sources
- thermal conditions. storage at very high, very low and/or very
variable temperature and/or humidity
- fumigation conditions: storage in contaminated or dirty
environment: indoor pollution ( =1Ccarbonyl pollution =1D: formaldehyde,
acetic/formic acid etc., pest infestation, fungus etc.)
- not stored in box/container
- stored horizontally
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d) Degradation through playback devices
- dirt can make debris/scratches
- not correct mechanically aligned can tear/stretch tape and pack
tape poorly
- not correct electrically aligned can cause signal
problems/inferior playback
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Well =13 this is not a comprehensive survey. If you want a more detailed an=
d
technical check you might for example find it in John W. C. Van Bogart:
=1CMagnetic Tape Storage and Handling. A Guide for Libraries and Archives =
=1D
published jointly by the American CLIR/Council on Library and Information
Records and NML/National Media Laboratory in 1995. You can download the
guide >from the Internet:
<http://www.clir.org/pubs/abstract/pub54.html>http://www.clir.org/pubs/abstr=
act/
pub54.html
I will come back to some of the problems more detailed in a later VIDEO
ART\e-monitor newsletter
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My concern =13 right now!
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My concern right now is that there should be done something not tomorrow
but NOW to preservation and conservation of the Danish cultural heritage
you have in video art.
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You can find lots of reports from conferences, endless papers on surveys
etc. on preservation/conservation of anything, also magnetic tapes/video
both from America and the European Union.
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EU established in 1994 ECPA / The European Commission on Preservation and
Access =1Cto promote activities aimed at keeping collections in European
archives and libraries accessible over time =1D. This also goes for tapes,
and ECPA states that =1CIn order to keep our documentary heritage available
for future generations of users, large-scale programmes must be developed
for its preservation =1D, so =1CThe ECPA aims to raise public awareness of
this issue and to impress the urgency of the situation on policy makers,
funding agents, and users =1D (http://www.knav.nl/ecpa/about.html)
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Lots of fine words and intentions - and lots of publications >from endless
of conferences etc with lots of fine technical and technocratic surveys and
decisions but as far as I can see with no practical implications - yet.=20
Even one of the latest surveys from ECPA: ECPA-report 14 (*) has to admit
that there is a =1Cbacklog =1D of tape preservation research, a lack of rea=
lly
experience and a gap of knowledge when it comes to video tapes.
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The development in the video field from analogue magnetic tapes to
digitization again raises the question about preserving the original
material. The ECPA-report 14 just mentioned seems to conclude that
concerning magnetic tape, digitization is the only means of preservation,
which means that the physical form of the first generation of video art
works may soon be completely lost by the continuing process of tape
deterioration.
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Another report (**) points to the complex situation concerning the digital
technology: Do we yet have the appropriate transfer technology and do we
have appropriate digital solutions? They find that digitisation should not
be hastily taken on board, and =13 most important, furthermore =13 that it
must be understood that every transfer is more or less preliminary.
Consequently they conclude that the original analogue carries must be
further preserved for future, better transfers, unless they disintegrate.
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As a result of the complex situation, the strategy for safeguarding video
materials should be that all efforts should be undertaken to prolong the
life of the existing carriers to the maximum possible extent. Emphasis,
therefore should be given to systematic research into prediction of life
expectancy of magnetic tapes and into measures to retard their decay. This
is, however, according to the ECPA-report, counteracted because the current
trend to reformat analogue information into digital form slows efforts to
preserve the original materials and because most of the financial resources
for tape conversation seems to be put into digital preservation.
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Even if you of course have to ask: =1CIs there intrinsic value (contra the
=1Caffectionable =1D value) in maintaining the original format? =1D, I think=
,
that for an artist invested in the unique characteristics of analogue video
imaging, the transfer of his art work to a compressed digital format may
cause unacceptable changes in the original images. From a preservation
perspective by this artist you want to preserve all information with as few
changes as possible (***).
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What can then be done? Passive or Active Precautions
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When it comes to prevent damage/degradation you can distinguish between
passive preservation versus active preservation / restoration /
conservation.
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Passive preservation is a preventive maintenance procedure. It is often
chosen because of financial constraints and/or reactions to mistakes in
previously performed conservation treatments. The main goal is to prevent
the tape from degrading prematurely.
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Active preservation / restoration / conservation is extensive actions =13
often very specialised technical =13 to restore detoriated or damaged video
tapes and preserve / conserve the tapes for future use.
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I will deal with both the passive and the active aspect in the next VIDEO
ART\e-monitor newsletters.
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Torben Soeborg
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Notes:
(*) Just one recent example: ECPA-report 14: Preservation Science Survey,
2000 =13 a joint venture between CLIR and EU prepared by Koninklijke
Bibliotheek, Den Haag, the Netherlands and published by ECPA in
co-operation with CLIR (the American Council on Library and Information
Resources). ISBN 90-6984-316-1, EU 23,00. You can find it at
http://www.knaw.nl/ecpa/publications.html
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(**) Report from The First International UNESCO Memory of the World
Conference, Oslo, Norway, 1996, Part II: Preservation and Access in the
Digital World, Paper 11 Dietrich Sch=FCller: Safeguarding audio and video
recordings in the long term. (Paragraph about =1CMagnetic Tapes =1D &
=1CCompact Discs =1D), http://www.unesco.org/webworld/memory/prelims.htm
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(***) I know that these lines have been expressed in a report, but I am
sorry to have lost my notes about the origin of the report.
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THE DANISH VIDEO ART DATA BANK is a non-profit agency for promoting Danish
video art outside Denmark
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The VIDEO ART\e-monitor is an e-mail edition of the former printed
newsletter =1Cmonitor =1D. Both were and are published with irrugular
intervals =13 =1Cmonitor =1D from 1985-86 up to no. 48 in december 2000 an=
d
=1CVIDEO ART\e-monitor =1D since February 2001. Editor: Torben Soeborg
(<mailto:soeborg@inet-uni2.dk>soeborg@inet-uni2.dk ).
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You can find the earlier editions of VIDEO ART\e-monitor on
www.videoart.dk/e-monitor . If you want to receive VIDEO ART\e-monitor
(free) send an e-mail to <mailto:soeborg@inet.uni2>soeborg@inet.uni2
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Denmark
tel/fax: +45-56.31.21.21
soeborg@inet.uni2.dk
http://www.videoart.suite.dk