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Re: [ARSCLIST] Acetate tape discolours tape box

Hi Bev:

OK, this is great. Now I understand a lot better. Thanks!

The key seems to be, better to get the tapes transferred sooner.

One big question remains -- why do some acetate backed tapes seem to get this worse than others? Again I say that I've never run into a vinegar-smelly AudioTape reel but often find this with Scotch 111 and even 131.

If someone is set up to look at breakdown amounts or pH or whatever you measure to see if vinegar has set in and how bad it is, I can probably dig up a few small samples of both Audiotape that is not obviously acidic and Scotch tape that is.

-- Tom Fine

PS -- I am told that Scotch and Audiotape 35mm mag-film from the late 50's into the 60's has a very bad tendancy to develop this problem and the film does shrink and curl. Now, why is this material so likely, indeed guaranteed to develop this and break down? Is it because of the thicker film base made of acetate, thus more concentrated material to develop and self-feed on the syndrome?

----- Original Message ----- From: "Bev Lambert" <BevLambert@xxxxxxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Tuesday, October 17, 2006 1:15 PM
Subject: Re: [ARSCLIST] Acetate tape discolours tape box

Not a dumb question if you havent been studying the preservation of film
and tape.
 The tapes that get "vinegar syndrome" dont start out that way. They
are on an acetate base and this means that after a period of time, it
can be 40 years, if kept in good conditions -ie not too hot or damp -
they start to deteriorate and one of the chemical results is the
offgassing off acetic acid, which smells like vinegar.  Once started the
chemical reaction is autocatalytic -feeds on itself and the stuff
degrades faster and faster.  You can slow it down by storing the tapes
in cold conditions -refrigeration, but you cant stop it.  You can absorb
some of the gas with molecular absorbers (available from Kodak), which
will help stabilize the tapes till you can copy them onto something more
stable -like a polyester base &/or digitize.
 Besides being a threat to the health of your sound collection, its a
health hazard.  The gas becomes more and more pungent and the acid
stronger -it'll burn out your mucous membranes if you keep inhaling it,
as well as giving you a terrible headache. Repeated exposures are
cumulative and not reversible.  So, if you have anything left to listen
to on those degraded, brittle, curly, broken tapes, you might not hear
it very well anyway.

tflists@xxxxxxxxxxxxxxxxxxx 10/17/2006 11:11 AM >>>
Perhaps a dumb question here -- what does the vinegar syndrome do to
the tape? I've had no problems
playing dozens of vinegar-smelling tapes over the years. Aside from
being typical old acetate (ie
brittle and easy to break and more likely than not to be curled on the
edges), they don't seem any
different from non-vinegar. I've come across many a box that looks like
this, but for bigger reels.

Are there tape types more likely to go vinegar than others? For
instance, it seems like most Scotch
111 reels, if they're old enough, smell at least vaguely like vinegar,
whereas it seems less
prevalent in AudioTape from the same era.

-- Tom Fine

----- Original Message ----- From: <Mwcpc6@xxxxxxx>
To: <ARSCLIST@xxxxxxxxxxxxxxxx>
Sent: Tuesday, October 17, 2006 9:21 AM
Subject: Re: [ARSCLIST] Acetate tape discolours tape box

In a message dated 10/17/2006 8:50:09 AM Eastern Daylight Time,
cpeterso@xxxxxxxxx writes:
Wow!  What a compelling picture.  There are a number of companies
make archival boxes specially designed to absorb offgasses, but I've
never seen such a visually strong argument for using them before.

"I recently came across a 3-inch reel of acetate tape, not in its
box, that showed the following pattern in the box. I recently came
across a
3-inch reel of acetate tape, not in its original box, that showed the
pattern in the box."

I've seen this before, but only on the 3" reels of this type in the
correspondence" boxes. I noticed it years ago, when the tapes were
new. Can you smell any acetic acid on the tape or box?

From using these tapes, usually sold in poly bags without boxes, in
the days
before cassettes, I remember that they had a distinctive smell when
new. The
boxes were sold separately, unfolded, so a new one could be used when
the tapes
were reused. I haven't seen this effect on name brand tapes, even the
tapes that smell strongly of vinegar (and always have).

One may need to do so some chemical analysis before drawing
conclusions. It
seems strange that a gas like the acid vapor would produce such a
sharp image
of the reel instead of diffusing throughout the box. Perhaps a larger
is responsible for the staining.

Mike Csontos

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