Biodeterioration and photographs

I'm a conservation restoration student and presently I am
researching biodeterioration on photographs. My research, at this
stage, is concerned with identification of fungus in negatives and
prints: isolation of fungi, cultivation in PDA and then examination
and identification. I want to know what genera and species were
found in other researches like this, and what major conclusions were
taken.

I've been reading about the modern photographic gelatine, and I know
that some biocide is added in the fabrication. Do you know since
when? What kind of biocides are used?

The few articles on biodeterioration in photographic materials that
I found just mention gelatine emulsion. What about other types of
photos like albumen and collodion? Does anyone know cases of fungus
contamination of these kinds of prints and negatives?

Another question is about the preferences of fungi. Most of the
times, the plastic-based films I saw, have very attached fungus (not
superficial), and mainly in the support side (not on the emulsion
side). Also it seems that mould attack is more intense in color
photographic films when compared with B&W. Do you share these
observations? What is the explanation for this? Is it related to
silver particles which could inhibit their growth?

I'll be very grateful to any one who can advise me on these matters
or give me some references on where to look.

Miguel Lourenco
Universidade Nova de Lisboa
Portugal


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                  Conservation DistList Instance 16:60
                 Distributed: Thursday, April 10, 2003
                       Message Id: cdl-16-60-016
                                  ***