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Subject: Diazo microfilm

Diazo microfilm

From: Michael McCormick <aa683>
Date: Tuesday, March 7, 1995
Charles Stewart <cstewart [at] library__berkeley__edu> writes

>Vinegar syndrome I associate with cellulose acetate bases, especially
>the earlier ones, and I didn't know this type of material was used for
>diazo in the mid-seventies.  Have you tried tearing a bit of non-imaged
>film (i.e., leader/trailer) as a crude test to be sure it's acetate?

Well, IPI announced a while ago that cellulose triacetate, which I
understand to be the latest generation of acetate film stock, is
subject to vinegar syndrome.  In any event, when I opened the drawer,
and it smelled like a pickle barrel, I knew there was a problem.  The
film buckling only confirmed it.

>If you think you are losing your diazo records to fading, then you'll
>probably want to have new duplicates made from the masters, if they can
>be located.  If not, it may be possible to create a silver copy from the
>diazo, depending on how far gone the things are.  We've had varying
>degrees of success here in duping diazo-to-silver, but if you can come
>out with something usable by this process, the product can at least be
>made and stored for permanence.

In this instance, I recommended re-filming.  While the original silver
negative was also available, the record series was county recorder's
deeds and mortgages, in large ledger volumes, filmed on 16mm, without
good descriptive targeting.  They're better suited to 35mm, and need a
finding aid to the microfilm edition.

But I took this as a cautionary note about diazo films, even for use
copies.  A silver, polyester base film, stored that long without use,
would likely have been pristine.

Michael McCormick

                  Conservation DistList Instance 8:73
                 Distributed: Wednesday, March 8, 1995
                        Message Id: cdl-8-73-006
Received on Tuesday, 7 March, 1995

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