[AV Media Matters] Audio Vinegar Syndrome

[sgreen@westernfolklife.org]

The recent references to vinegar syndrome in audio collections
prompts me to ask something I've been curious about for some time.

Most articles that mention vinegar syndrome--  whether refering to
film or magnetic tape--  say that it can "infect" other acetate
based materials nearby.  Just now on this list, a person said it was
"contagious."  I'm interested by these medical type analogies and
wonder if anyone could provide a good explanation of what exactly
happens that would cause vinegar syndrom to spead like a disease to
adjacent materials?

I can more easily understand, say, two reels of motion picture film
locked up tight together in a cannister than say, two reels of audio
tape in boxes next to each other on a shelf.

For readers unfamiliar with vinegar syndrome, there is an
explanation offered by Gilles St.-Laurent in his article "The
Preservation of Recorded Sound Materials" a web-based text of which
can be found on Graham Newton's site at
http://www.audio-restoration.com/gilles.htm. Look under the heading
for "Magnetic Tape Backing."

Basically, the author explains "When the acetate is degrading--
giving off acetic acid-- it will start to take up more moisture. The
process of self-destruction is auto-catalytic, once it has started
it will continue with ever increasing speed; no solution for its
interuption has yet been found."  And again, here is the medical
analogy: "Tapes afflicted with the vinegar syndrome will "infect"
healthy tapes."

So can anyone take a stab at explaining the process by which other
materials are "infected."?

Thanks.

Steve Green
Western Folklife Center
501 Railroad Street
Elko, NV 89801
sgreen@westernfolklife.org