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Re: odors coming from Audio and video collections



I thought it may be helpful to comment on some of the comments.........

First of all, "vinegar syndrome" specifically relates to the break down of
acetate based materials. Acetate has been and is used as a support on many
different types of products, but motion picture roll film and other types of
roll films are  usually the culprit in these situations because there is a
high density of the material usually stored in a sealed or semi-sealed
container.  Once the concentration of acetic acid reaches a certain level,
the reaction becomes auto catalytic - which means that the film literally
eats itself - i.e. the acetic acid present causes more film to break down
into more acetic acid and so forth. Depending on the severity of the problem
there are a number of remedies - but ultimately the solution is to recopy
the film and make a new copy. This is NOT done by Kodak, but IS done by
professional motion picture film laboratories who specialize in this type of
work (VidiPax is NOT one of them).

Videotape has NEVER repeat NEVER been manufactured on acetate based stock -
it has been made on a variety of PET type materials - to most of us that
means polyester. Polyester does NOT get vinegar syndrome since there is no
acetate at all. Videotape does have other major problems which cause
degeneration  but vinegar syndrome is not one of them.

Audio tape HAS been manufactured on acetate, but it was not very popular and
while it does exist and therefore it could develop vinegar syndrome, the
reality is that it rarely happens. There are many theories why it is not a
major problem, but it probably gets back to the density issue. At vidipax we
have restored thousands of audio tapes and while they too have major
problems, vinegar syndrome is extremely rare, and I have never seen an audio
reel to reel acetate based tape degenerate at anywhere near the level of
motion picture film.

There are magnetic films that are acetate based, and if Van Bogart referred
to magnetic FILM, then this is what he is referring to NOT MAGNETIC TAPE.
Magnetic Film is VERY different material then regular audio or videotape -
it is magnetically coated acetate film that is used in motion picture
productions. It basically looks like film except it is usually either brown
or gray which is the magnetic coating. It has sprocket holes and can be
either 16mm or 35mm. Unfortunately there have been major problems with these
types of films getting vinegar syndrome as well as other problems. In some
respects this media type has the worst of all worlds from a preservation
point of view - it has the problems of both magnetic binders and acetate
base films.

The best way to slow down the process is to keep the materials cool and dry.
There are products like molecular sieves which will slow down the process
somewhat but ultimately you really have to recopy the film and the longer
you wait the worse it will be - so the remedies suggested in some of the
postings may slow down the degeneration but WILL NOT reverse or halt it.
With film the materials can be frozen in the CORRECT ENVIRONMENT i.e. low
humidity. Magnetic tape (audio or video tape) should also be kept cool and
dry but NOT frozen. There is a great deal of documentation on this
ubject  - for further information one might consult the SMPTE (Society of
Motion Picture and Television Engineers) and ANSI for standards and
recommended practices for the long term storage of motion picture,
photographic, and audio and video materials.

I hope this helps untangle things a bit.  (ha ha)
jim

Jim Lindner - President
VidiPax - The Magnetic Media and Information Migration Full Services Company
Telephone 212-563-1999
www.vidipax.com
Moderator of A/V Media Matters@topica.com


> -----Original Message-----
> From: Archives & Archivists [mailto:ARCHIVES@LISTSERV.MUOHIO.EDU]On
> Behalf Of Jones, Virginia
> Sent: Thursday, May 11, 2000 2:54 PM
> To: ARCHIVES@LISTSERV.MUOHIO.EDU
> Subject: Re: odors coming from Audio and video collections
>
>
> Rob:
> Vinegar syndrome can occur in any "acetate" base material.  Dr. John Van
> Bogart of the National Media Lab defines vinegar syndrome as
> "characteristic
> of the decomposition of acetate based magnetic tape where acetic acid is a
> substantial by-product that gives the tape a vinegar-like odor.  After the
> onset of the vinegar syndrome, acetate tape backings degrade at an
> accelerated rate - the hydrolysis of the acetate is catalyzed
> further by the
> presence of acetic acid by-product."  ("Magnetic Tape Storage and
> Handling,
> A Guide for Libraries and Archives", Dr. John W. C. Van Bogart,
> published by
> The Commission on Preservation and Access, June 1995)  Both your
> audio tapes
> and your video tapes are a form of magnetic tape.  Microfilm and
> photographic negatives manufactured with an acetate base material are also
> susceptible to vinegar syndrome.  High humidity accelerates the onset of
> vinegar syndrome as well as some other mag tape binder problems so you may
> want to investigate how much the proximity to the pool area is affecting
> your storage environment.
>
> Ginny Jones
> (Virginia A. Jones, CRM, MIT, LIT)
> Newport News Waterworks
> Newport News, VA
> vjones@ci.newport-news.va.us
>
> > -----Original Message-----
> > From: Rob Dishon [mailto:rdishon@LAGCC.CUNY.EDU]
> > Sent: Thursday, May 11, 2000 1:47 PM
> > To: ARCHIVES@LISTSERV.MUOHIO.EDU
> > Subject: Re: odors coming from Audio and video collections
> >
> >
> > But doesnt vinegar syndrome only effect negatives...  I wasnt
> > aware the modern day audio and video tape had the same
> > properties as negatives.   My photo and negative collections
> > are in another storage area.
> >
> > A posting from the Archives & Archivists LISTSERV List!
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> > Problems?  Send e-mail to Robert F Schmidt <rschmidt@lib.muohio.edu>
> >
>
> A posting from the Archives & Archivists LISTSERV List!
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>
> Problems?  Send e-mail to Robert F Schmidt <rschmidt@lib.muohio.edu>
>

A posting from the Archives & Archivists LISTSERV List!

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Problems?  Send e-mail to Robert F Schmidt <rschmidt@lib.muohio.edu>