[spectre] VIDEO ART\e-monitor: Preservation of video Part 3: Passive and
Active actions
Torben Soeborg
soeborg@inet.uni2.dk
Tue, 9 Apr 2002 15:34:31 +0200
VIDEO ART\e-monitor 11 =13 THE DANISH VIDEO ART DATA BANK
April 10, 2002
Content:
Preservation of video Part 3: Passive and Active actions
* Passive preservation* * A) Refreshing* * B) Remastering* * C)
Multiple Tape copies* * Storage Recommendations / Guidelines* * A)
Archival Storage* * B) Access Storage* * Storage Possibilities* *
Active Preservation 7 Restoration / Conservation*
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Passive preservation
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We are still speaking about older tapes e.g. analogue recorded video tapes.
I will first discuss what is usually called =1Cpassive preservation =1D. Th=
e
main goal is to prevent the tape >from degrading prematurely with simple.
precautions
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Three aspects of passive preservation could be:, a) exercising/refreshing,
b) remastering and c) multiple copies
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Ad a) Refreshing
Exercising or refreshing is a periodic winding and rewinding of tapes,
especial if the tape is not played very often. It is recommended for
several reasons. It should reduce the print-through =1Cecho =1D effect tha=
t
can occur on analogue tapes when stored over a long period. It is at the
same time a retensioning of the tape which is recommended because prolonged
tape pack stresses could cause damage to the tape. The winding-rewinding
should be done at regular intervals. Some manufacturers recommend to do it
every three years but it is best to check with the manufacturer of the
tapes you use to determine if and how often retensioning is needed.
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Ad b) Remastering
By remastering or transcription you transfer (copy) the content of an old
tape onto a new tape before the old tape detoriate rather than trying to
preserve the old tape. Since tape manufacturers often make improvements
from time to time it is a good idea to transfer the content of a tape made
early in the life of a format to a new tape of the same format.=20
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It is often suggested that this should be done every 10 years. The problem
is, though, that even with the best and technically optimized equipment you
always get a reduction in quality when you copy from one generation to the
next.
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Instead of transferring to the same tape format it is often recommended to
transfer to a better quality (but still analogue) tape format. It could be
to transfer from VHS to S-VHHS, from Low Band U-matic to High Band U-matic
to Betacam, from Betacam to Betacam SX.
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I think the American Magnetic Media Restoration Company Viditex expresses
quite precisely my concern about remastering, when they state that =1CThe
challenge is to remaster a tape so that it integrates contemporary media
techniques, but does not excessively compromise the integrity of the
original material =1D (*).
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=46or safety reasons the old tape should be kept until the transcribed tape
is again transcribed to an even newer generation. In this way you will
always have two examples of the video work =13 and this brings us forward t=
o
the next aspect.
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Ad c) Multiple Tape Copies
This is the best way to minimize risk to valuable information contained on
video tape. With at least two copies you are safeguarded if (and that is
important) they are safely stored at separate storage locations one in an
archival storage and the other in an access storage and only this should be
available for playback use.
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Even better would be to have four copies: 1. The Original Master Tape, 2. A
Preservation Copy, 3. A Duplication or Working Copy, and 4. The Access Copy
(or Copies).
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1) The original Master should be archived under optimal conditions
(see our next VidoeART\e-monitor) and never accessed unless something
happens to the Preservation Copy.
2) The Preservation Copy or Preservation Master is a copy of the
original Master Tape. It should be as close to the original Master as
possible and made without using any type of enhancements or other
techniques. This tape should also be stored under optimal conditions and
only accessed if anything happens to the Duplication Tape.
3) The Duplication Copy saves any risk to the Preservation Master and
the Original Master and it should be possible to make faithful Access
Copies of this for different types of access, distribution, sales, etc. It
can be stored under less optimal conditions than the Master and the
Preservation tapes.
4) The Access Copy or perhaps even Copies is =13 as the name indicate=
s
=13 for general screening and access. The copies should be made on the most
common used and cheaper formats.
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Access policy of a video archive should be: =1CNo access without
preservation =1D. The MultipleTape Copies strategy is probably the best way
to secure this.
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=46inally a few more recommendations ( & and you might want to add more):
* Do always use high quality tapes from a well known brand name* *
Do always use a strong and stable tape container* * Do always use
non-acid and =1Cnon-peeling =1D archival labels on the tape*
* Do always rewind the tape after use* * Do store the tape vertical*
* Do keep/store the tapes with care: not too hot, not too cold, not
too humid *
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With the last recommendation we touch upon the broad aspect of how best to
store archives of video tapes =13 and here we are moving on the borderline
between passive and active preservation. Let us take a closer look at
storage problems
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Storage recommendations / guidelines
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You can find many guidelines for the optimal storage of magnetic tapes.
=46ollowing the strategy above under =1CMultiple Tape Copies =1D you might
distinguish between a) Archival Storage and b) Access Storage. In the first
type you store the original masters and the preservation master. In the
last type you might store the duplication copy and you store the access
copies.
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a) Archival Storage
Archival storage should provide storage that preserve and safeguard the
tapes for as long as possible. The storage room should be a room dedicated
for storage and this means very strict demands =13 for example:
=B7 Windowless
=B7 Free of dust
=B7 Not close to magnetic fields
=B7 Possible to filter out corrosive gasses and other form for
air/room contamination
=B7 Possible to control indoor climate conditions
=B7 Able to maintain the conditions for two days in case of power fa=
ilure
=B7 Storage temperature around 5 degrees C ( 40 degrees F)
=B7 Temperature variation less than plus/minus 2 degrees C
=B7 Relative humidity: 20-25 %
=B7 Humidity variation less that plus/minus 5-10 % RH
=B7 Fireproof
=B7 No sprinkler system
=B7 No use of wood/cardboard boxes and shelving
=B7 Periodic inspection and periodic rewinding/exercising of tapes
=B7 Limited access
And of course the above mentioned recommendations: rewind the tape before
storing, use strong, stable, clean and dustfree tape box, store the tape
vertical, etc.
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Not all the recommendations above are agreed upon by all archivists and
some might want to add more, so please don =19t consider the survey as
=1Cfinal =1D. You must do your own research and make your own decisions (als=
o
according to your needs and your financial possibilities! (take a look for
example at the reports mentioned in Note ** and ***).
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b) Access Storage
The access storage provide storage for that allows immediate access to the
tapes, and the demands are not as strict as to the archival storage. You
should still be able to control the indoor climate to some degree, but the
temperature could be between 15 and 23 degrees C (variation not more than 4
C) and relative humidity between 25 to 55 % (variation not more than 20 %
RH). Anyway it is a good idea to follow most of the other recommendations
for archival storage rooms.
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Storage possibilities
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Both in the ECPS-report 14 (**) and Magnetic Tape and Storage Handling: A
guide for Libraries and Archives (***) referred to in VIDEO ART\e-monitor
No. 10 you can find more details about storage conditions and
recommendations
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Of course it is easy to draw up the ultimate storage conditions but it is
often not possible especially for smaller archives to follow these. You
have then mainly to relay on passive preservation and with the ultimate
conditions in mind you then have to do the best possible.
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Active Preservation / Restoration / Conservation
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What are the strategies? What can be recommend? What can be done if we look
more upon what you could call active preservation and active
restoration/conservation: Active actions if the video tape is already in a
bad stage, detorieting or damaged? I will deal with this in the next VIDEO
ART\e-monitor
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Notes:
(*) Vidipax: The Magnetic Media Restoration Company, 450 West 31st St. 4th
=46loor, New York, NY 10001, USA =13 http://www.vidipax.com -
<mailto:info@vidipax.com>info@vidipax.com =20
Vidipax is the largest and most advanced media restoration company in the
world.
You will find the quotation on http://www.vidipax.com/librefm.html in the
third paragraph
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(**) 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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(***) John W. C. Van Bogart: =1CMagnetic Tape Storage and Handling. A Guid=
e
for Libraries and Archives =1D published jointly by the American CLIR/Counci=
l
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
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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 a=
nd
=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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Themstrupvej 36, Dk-4690 Haslev
Denmark
tel/fax: +45-56.31.21.21
soeborg@inet.uni2.dk
http://www.videoart.suite.dk
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