[spectre] Torben Soeborg: VIDEO ART\e-monitor No. 12
Andreas Broeckmann
abroeck@transmediale.de
Wed, 15 May 2002 22:06:11 +0200
From: "Torben Soeborg" <soeborg@inet.uni2.dk>
Subject: VS: VIDEO ART\e-monitor No. 12
Date: Wed, 15 May 2002 18:06:52 +0200
VIDEO ART\e-monitor No. 12
May 16, 2002
Content:
1. Preservation of Video Tapes, Part 4:
Magnetic Tape Degradation
Tape Analysis and Evaluation
Inspection of Video Tapes
Basic Priority Planning
2. New Book: Media Art Interaction
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1. Preservation of Video Tapes, Part 4
Magnetic Tape degradation
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:
a) Technical degradation of tape:
- binder degradation
- lubricant loss
- magnetic particle instability
- tape backing/substrate deformation
b) Degradation by handling of tape:
- dropping tape/cassette
- contamination by dirt, dust, fingerprints, food, cigarette
smoke, air pollution etc.
- not acclimatised to the playback environment
- exposed to sunlight, water or other types of fluid
- not rewinding tape after use
- frequently accessed and played
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 ( carbonyl pollution : formaldehyde,
acetic/formic acid etc., pest infestation, fungus etc.)
- not stored in box/container
- stored horizontally
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
Tape Analysis and Evaluation
The first step toward preservation is of course that you are able to
effectively analyse and evaluate the conditions of videotapes in
collections/archives. Not only you have to know:
1. The physical properties of videotapes2. 3. the factors/conditions to
tape detoriation & but also4. 5. how to discover and identify the
signs of detoriation6.
Ad 1) I will not describe the physical conditions: how a tape is build up,
but refer to the Internet, where you may find technical descriptions of the
physical properties (1)
Ad 2) The factors leading to detoriation I have already dealt with to some
extent in VIDEO ART\e-monitor No. 10 (2)
Ad 3) You can also find descriptions of different ways to identify signs of
detoriation on the Internet. I will try to summarise what you can do.
Inspection of Video Tapes
To put it very short: you do it through visual inspection and playback.
If you can see that the tape is not wound evenly and this could be
coursed by starting and stopping the playback on and off, using high speed
fast forward/rewind or a poor adjusted playback machine - you should first
rewind it properly and then evaluate it through playback. With an open reel
tape you might also be able to discover chemical detoriation. This is
difficult to evaluate visually with tapes in cartridges/cassettes.
Using playback you should be able to evaluate problems like video and audio
noise, intensity of blips, timing problems, colour shift/distortion and
audio problems.
The American company SPECS BROTHERS Audio & Video Tape Restoration authored
the following 7-Step Physical Inspection plan for the American National
standards Institute Subcommittee on Magnetic Tape as simple and basic
inspection process to sample conditions of magnetic tape:
1. Check physical container for damage that compromises the
structural integrity of the container itself2. 3. Check the interior of
the container and the edges of the tape for patterned black, brown, or
mustard coloured contamination and for fuzzy or thread-like grows that
indicate the presence of fungus4. 5. Smell the tape as soon as it is
removed >from the container for abnormal smells6. 7. With light
source above and slightly behind tilt the tape edge-on at
approximately 45 degrees away from the light source and inspect tape
pack8. 9. Check the tape edges and the reel/cassette/cartridge for
particulate contamination and for signs of staining that may indicate
liquid contamination10. 11. Check the tape edges for white powder or
crystalline residue and check the interior of the container for
black/brown flakes of oxide12. 13. If the tape is reel to reel, allow a
few outer wraps to hang loose and examine for physical distortion and
binder/base adhersion failure.14.
You can find these 7-Steps more elaborated in the essay White Paper at
the SPEC BROS web site (3).
Basic Priority Planning
If you have a large collection of video tapes it might be too expensive
and too much work to preserve all the tapes. You might have to evaluate
the tapes and decide on priorities. To this use The Experimental TV Center
in New York has made a list of 12 questions (4).
Here are some of the questions:
- What is the value of the tapes? Why are they important to save?
Who will use them?
- Do you have the legal rights to the tapes?
- Are some more valuable, unique, endangered?
- What stage in the production process do the tapes represent? Are
they masters, sub-masters, camera or audio originals, viewing copies?
- What are the overall conditions of the tapes? Which tapes are on
obsolete or endangered formats? Which are the oldest?
Jim Lindner has in the essay Videotape Restoration Where Do I start?
made up a similar Check List for Prioritizing Candidates for Video Tape
Restoration (5). You add points for every time you have to answer yes
when evaluating a tape and tapes with the highest numerical values
should be restored first:
* Does the tape exhibit any symptoms of "sticky shed syndrome"
(squealing during playback, frequent head clogging, flaking or sticky
surfaces)? If yes add 5 points * * Is the tape a single copy and
exhibit any symptoms of "sticky shed syndrome" (squealing during
playback, frequent head clogging, flaking or sticky surfaces)? If yes
add 5 points * * Is the tape a single copy? If yes add 5 points *
* Is the tape an obsolete format? If yes add 5 points * * Is
the tape physically damaged? If yes add 4 points * * Is the tape the
highest quality element in the production? If > yes add 3 points * *
Is the tape an early example in a format popular format ? If > yes
add 3 points * * Is the tape 10 years old or younger? If yes add 2
points * * Is the tape between 10 and 15 years old? If > yes add
3 points * * Is the tape between 15 and 20 years old? If > yes
add 4 points * * Is the tape 20 years or older? If yes add 5 points
(older than 25 years add one point per year over 25 (example 30 years old
add 10 points) * * Has the tape been in a stable environment with
proper temperature and humidity control If yes deduct 4 points *
Jim Lindner assumes that all the candidate tapes you check are of equal
value to you and/or your organisation/agency/archive.
Torben Soeborg
Notes:
(1) Try for example: http://www.clir.org/pubs/reports/pub54/2what_wrong.html
(2) http://www.videoart.suite.dk/e-monitor/newsletter-10.htm
(3) http://www.specsbros.com/whitepaper.html
(4)You can find the questionnaires on
http://www.experimentaltvcenter.org/history/preservation/pres_start.html
(5) You can find this essay on Stanford University s web site:
CoOl/Conservation OnLine. Resources for Conservation Professionals
:http://palimpsest.stanford.edu .
Under Conservation Topics click on Video preservation and then
under Jim Lindner on the essay Videotape Restoration Where Do I
Start
(or go directly to
http://palimpsest.stanford.eddu/byauth/lindner/lindner2.html )
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PS: The two next VIDEO ART\e-monitors will also deal with aspects of video
tape preservation:
No. 13: Preservation of Video Tapes: What Can Be Done
among other things:
Professional Help
What is done?
Why tapes need to be cleaned differently
Wanted: A Common Strategy
Once Again: The Ethical Considerations
No. 14: Preservation of Video Tapes: Catalogue
among other things:
Need also help for preservation/conservation
Importance of compatible cataloguing Video History Project
Electronic Arts Intermix suggestions
IMAP tutorial/guidelines + template
Online cataloguing tutorial Video History Project
European examples
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2. New Book: Media Art Interaction
Rudolf Frieling & Dieter Daniels (edit):
Media Art Interaction: The 1980s and 1990s in Germany
Springer Verlag, Wien, ISBN 3211834222
This new anthology is a sequel to the book Media Art Action - The 1960s and
70s in Germany and includes (like the first anthology) a CD-ROM with
numerous audiovisual examples of media art illustrating many of the
references made in the essays.
The essays in the anthology are all printed in German and English. They are
edited in four sections: Video/Concepts, Action/Music/Crossculture,
Interaction Art and Networking/Strategy. One of the great forces of the
book (like the first one) is that many of the included essays otherwise are
hard to find.
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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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intervals monitor from 1985-86 up to no. 48 in December 2000 and
VIDEO ART\e-monitor since February 2001. Editor: Torben Soeborg
(<mailto:soeborg@inet-uni2.dk>soeborg@inet-uni2.dk ).
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