Archived posting to the Leica Users Group, 2001/01/30

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Subject: Re: [Leica] Re: @#&$$& Watermarks!!
From: "Mike Durling" <>
Date: Tue, 30 Jan 2001 19:24:37 -0500
References: <>

There are different types of acetate film base.  Some, which I have heard
called diacetate, give off acetic acid and can deterioriate rather
dramatically.  They look like nitrate but don't burn.  The good acetate
(triacetate?) seems rather stable but will shrink over time.

I take care of an archive of old movie film.  Shrinkage is more of a problem
for something that has to run through a projector or printer.  The same film
(60 years old) that could not be projected will run nicely through a
sprocketless film-to-tape transfer machine, and if its Kodachrome the color
will even be good!  Until recently this film was not even stored under ideal
temp and humidity conditions.  Proper storage will extend the life of film
quite a bit.

Mike Durling

> I don't selenium tone my negatives but it is considered a very prudent
> step for ensuring image permanence. This is no joke.
> There was an interesting thread in a while back
> regarding the acetate base of all 35mm film (except maybe TP and a few
> other oddities) which is apparently the first thing to go, on the order
> of 50yrs or so, depending on storage conditions, etc. Our negatives are
> not as permanent as we think.
> Byron.

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