Deterioration of color microfiche

Angela Thompson <angela.thompson [at] ng-london__org__uk>, on behalf of
Margaret Hey, writes

>    4.  Two types of Ilford film are available--camera negative and
>        duplicating, all on polyester base, 4mil and 7mil
>        thicknesses, roll and sheet form.
>
>        Camera negative roll film is:
>            Ilfochrome Micrographic CMMF4 3.5 x 30m RKS30 E1 DPP
>        Duplicating roll film is:
>            Ilfochrome Micrographic 1M CMP F4 3.5 x 30m E1 DPP
>
>    5.  I obtained this information on Nov 27 from the London Head
>        Office who told me that the film is stocked in Switzerland
>        even if not in all Ilford agencies world-wide so there
>        should be no problem in obtaining it.
>
>These films are more expensive than other micrographic color
>products but film cost is only a tiny proportion of microfilming
>expenses. Besides, initial expense but lasting hundreds of years
>against lower expense repeated every 15 years: is there a decision
>to be taken?

We are experimenting with the Ilford film, and I would like to note
that its color reproduction and saturation, and its resolution are
very impressive.  However, I would also like to say that the
material is a *reversal* film, that is, it is processed as a direct
positive.  Both the camera master and use copy are positive in
polarity.

Also, the fact that the Ilford film is 8 times more expensive than
B&W has to figure in project planning.  Certainly the persistence of
the material and its ability to capture information encoded in
color, such as on maps, makes it a useful preservation tool, but one
cannot ignore its expense.  Its use really can only be justified on
high value, heavily used, and fragile items.

Michael McCormick

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                  Conservation DistList Instance 10:53
                Distributed: Thursday, December 5, 1996
                       Message Id: cdl-10-53-002
                                  ***