Pink fingerprints on photographic print

Tim Vitale <tjvitale [at] ix__netcom__com> writes

>I have seen a few pink fingerprints on B&W prints before, but I've
>never had to define the source.

My understanding is that many modern papers contain dyes (generally
pink or blue) which are added as emulsion sensitizers or internal
filters.  These dyes generally become colorless in an alkaline
developer and may also be water soluble.  However, if traces remain,
they may reactivate in an acid environment, as sometimes occurs with
anti-halation dyes in deteriorating cellulose acetate films.

Perhaps the fingerprints were acid enough to cause such a color
regeneration within the gelatin layer.  The local salts and
attendant moisture may have helped catalyze the reaction.

Loren C. Pigniolo
Archivist / Preventive Conservation Specialist
Photographic Negatives Research Project
San Francisco, CA, USA
negatives<-a t->earthlink< . >net
925-788-2231 (cell)


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                  Conservation DistList Instance 19:11
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                       Message Id: cdl-19-11-003
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