Re: [ARSCLIST] Acetate tape discolours tape box

[Bev Lambert <BevLambert@xxxxxxxxxxx>]

You are right. IPI only makes claims for the use of AD strips on acetate
base FILM. 
Joe Iraci and his colleagues at CCI would be able to tell you more
about the audio media.  It seems tape has had more of the SSS -sticky
shed syndrome than VS. I got a bit carried away with the acetic acid
detection...Bev Lambert

>>> arclists@xxxxxxxxxxxxxxx 10/18/2006 12:47 PM >>>
At 10:39 AM 10/18/2006, Bev Lambert wrote:

I have used the A-D strips and have a package, but the general 
consensus is that they do not work reliably on tapes. I don't recall 
all of the details that others have observed and someday I will 
pursue this with IPI, but their focus is film.

As to the date for nitrate film, several online references suggest 
that Kodak discontinued it in 1951 or 1952 and that it was 
discontinued worldwide by 1955.

I recall my mentor telling me years ago (he's been dead for years) 
that when he got back from WWII he threw out all his nitrate 
negatives as they had started to decay. For amateur purposes, safety 
film was introduced in the 1930s, I believe.

So, I would suspect that any amateur film (motion or still) from the 
late 1930s on would be safety film (I believe Kodak never made an 
amateur nitrate film, but could be wrong on this) and only pro motion 
picture films used nitrate into the early-mid 1950s. Of course, this 
is date of manufacture. Obviously films hang around for a long time.

It is my understanding that freezing makes nitrate essentially safe 
and stops the decay that turns it into nitroglycerine.

Cheers,

Richard


>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
>

Richard L. Hess                   email: richard@xxxxxxxxxxxxxxx 
Aurora, Ontario, Canada       (905) 713 6733     1-877-TAPE-FIX
Detailed contact information:
http://www.richardhess.com/tape/contact.htm 
Quality tape transfers -- even from hard-to-play tapes.