Nitrate negatives

Frank A. Reynolds <fr0c [at] andrew__cmu__edu> writes

>We have a metal box in which there are a number of negatives that I
>suspect are nitrate.  I have read that one way of testing for
>nitrate negatives is by placing a small piece of film in a test tube
>of trichloroethylene to see if it sinks when completely wet.  I
>understand that trichloroethylene is very toxic, and I can only
>obtain a liter of it which is far more than what I need.
>
>    1.  Does anyone know of another testing method of testing for
>        nitrate film?
>
>    2.  Is there someplace the will test film (for a reasonable
>        fee)?

Identification of nitrate negatives is often possible without
testing. For example, edge printing, deterioration characteristics,
and age of the material can all be used to characterize film-base
materials. It is often possible to avoid destructive testing all
together. For example, a negative from 1915 will be nitrate because
no other film-base materials, such as acetate or polyester were yet
being used by the photographic industry. Monique Fischer and I have
written about the care and identification of film-base materials in
Topics in Photographic Preservation volumes 5 and 6. This
information can also be found as an appendix in Care of Natural
History Collections and at the CoOL web site
<URL:http://palimpsest.stanford.edu/byauth/fischer/fischer1.html>.

Andrew Robb
Senior Photograph Conservator
Conservation Division
Library of Congress

Monique Fischer
Associate Conservator
Northeast Document Conservation Center
mfischer [at] nedcc__org

                                  ***
                  Conservation DistList Instance 13:23
                 Distributed: Tuesday, October 5, 1999
                       Message Id: cdl-13-23-003
                                  ***