Re: [ARSCLIST] Acetate tape discolours tape box

[Bev Lambert <BevLambert@xxxxxxxxxxx>]

Oh yes I forgot to mention that IPI (Image Permanence Institute)
developed a method for detecting the stage of deterioration of acetate
based film.  I dont see why this cant be used with audio tapes as well. 
If you contact them (www.imagepermanenceinstitute.org) they will give
you the necessary information.  There is a kit including 250 A-D (acid
detection) strips), instruction guide and a colour reference pencil.
They also sell a  Storage guide for Acetate Film publication. The
process involves putting a little blue strip into each tape package
-box, envelope whatever, leaving it overnight -they tell you how long
depending on the storage temperature- and then comparing the colour of
the strip to the colour bands on the pencil. The amount of colour change
indicates the level of degradation and therfore whether existing storage
conditions are adequate for preservation. 
  As to why some more than others according to brand, its hard to say,
as many of the manufacturers are quite proprietory about their
formulations. So, other than the history of storage conditions and
handling...???
  And for film from the 50s: that is most likely NITRATE, much more
scarey.  Especially moving picture film - by the nature of which it is
rolled tightly against itself, previously in non ventilated metal tins,
and those tins stored close together in small rooms, again without
ventilation..the chemical breakdown creates heat...its literally an
explosive situation. Nitrate is not a stable material, it breaks down
into nitric acid, &/or nitrogen gas!  If someone were to drop a tin of
deteriorated nitrate film in that storage situation, the result could be
an explosion, instantaneous fire igniting the rest of the collection. 
Thats not to say all nitrate film is bad- but it needs to be kept under
carefully controlled and monitored conditions, and copied to a more
stable base before deterioration sets in.  Thats why the big
repositories of film in the US have built literally underground bomb
shelter type storage facilities.  You probably know this: the first
moving picture film is on nitrate and  even though they stopped
producing it when acetate was introduced, it was still around of course
and filmmakers used it. Nitrate has a beautiful asthetic quality they
felt they could not get in other types of film-of course its all black
and white. Still photographic negatives have the same history but dont
pose quite the threat because they are small and usually each is
separated by its own enclosure.  

Also I neglected to tell you who I am.  I am not a specialist in film,
but had to find out about all these media to advise the archives I work
for on proper storage for their collections. You can find out more from
the Canadian national archives, now called Library Archives Canada, and
large repositories in the US such as Library of Congress and research
institutions such as IPI. They all have web sites with Preservation
pages.

Beverley Lambert, Conservator
Provincial Archives at The Rooms
St. John's, Newfoundland & Labrador, Canada
709-757-8057 Fax: 709-757-8031

>>> tflists@xxxxxxxxxxxxxxxxxxx 10/17/2006 3:22 PM >>>
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
> that
>> 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
> original
>> 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
> following
>> pattern in the box."
>>
>> I've seen this before, but only on the 3" reels of this type in the
> "tape
>> correspondence" boxes. I noticed it years ago, when the tapes were
> relatively
>> 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
> Kodak
>> 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
> molecule
>> is responsible for the staining.
>>
>> Mike Csontos