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Subject: Deterioration of color microfiche

Deterioration of color microfiche

From: Doug Nishimura <dwnpph>
Date: Thursday, November 21, 1996
Anita Shaughnessy <anita.shaughnessy [at] mvs__udel__edu> writes

>We have some color microfiche that is developing a pinkish hue.

Since magenta staining, particularly in transparencies, is virtually
unheard of, I assume that it is the image that is turning magenta
causing the fiche to look like most of the educational films I
remember seeing in school.

Color fiche comes in two general types. Ilford produces the only
silver dye bleach film (specifically made for microform
applications) now called Ilfochrome (formerly Cibachrome.) This
fiche has exceptionally good dye stability in the dark, and even in
the light, is significantly better than chromogenic film.

There is no such product as color chromogenic microfilm and what
they use instead is cut motion-picture print film. In many of the
older products, the most fugitive dye in dark fading has been cyan,
followed by yellow. Thus images stored in the dark have tended to
turn orangish or reddish (magenta + yellow) and eventually magenta.
When exposed to light (light fading), the weakest dye has tended to
be magenta, causing the images to turn rather green or blue.

>As I understand it this is an inherent problem with color film, and
>the only way to stop it is cold storage.

Yes. (Or at least slow it down significantly.)

>The microfiche was produced in 1979.  This seems a very short time to
>have this much degradation.

Back in 1979, these color materials lost about 10% of the cyan dye in
about 5 years when stored at 75 F/40% RH. Colder temperatures will
definitely slow this down. Silver dye bleach film stored under the
same conditions would take several hundred years to reach the same
point of deterioration.

>Short of putting a freezer in our microforms area is there any other
>way of halting or slowing down the process?

The rate of deterioration is governed by both RH and temperature so
I'm afraid that the answer is no.

>Has anyone else encountered this problem?

Everyone else with chromogenic microfilm should have the same

>And what was your solution? Should I just recommend that the microfiche >be replaced?

Assuming that the original material is still available, you might
want to consider re-filming. It is very likely that there is so
little of the original color left in this fiche that it isn't worth
keeping (unless it is the only copy of this material available.)

Having heard the difference in dark stability between the two types
of film, you are left with the decision of which to use. Silver dye
bleach has the better stability, but it is more expensive. The other
concern is how the film will be used. There is no sense in spending
the extra money for a more stable image if the film will be employed
as a "use" copy. (I often see so-called "archival masters" being
used as use copies.) It is likely that the film would have to be
replaced because of scratches and handling damage in the not too
distant future. The other option is to make a cheaper chromogenic
master and put it into cold storage. A chromogenic copy can be used
as the use copy. The frozen master would only be used to make use
copies as needed.

However, if you simply want to keep a preservation master without
needing to resort to cold storage, the silver dye bleach fiche would
probably be worth the extra cost.

Be aware that the stability of chromogenic technology has improved
significantly since 1979. Less stable dyes have been replaced by
more stable ones and in most films, the yellow dye is now the most
fugitive in the dark. For comparison (using the weakest link), a
typical film in 1979 lost about 30% of the cyan dye in just over 20
years. A typical 1993 vintage film under the same conditions would
lose 30% of the yellow dye in just over 40 years.

Douglas Nishimura
Image Permanence Institute

                  Conservation DistList Instance 10:50
                 Distributed: Monday, November 25, 1996
                       Message Id: cdl-10-50-001
Received on Thursday, 21 November, 1996

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