It's been known for a good many years that a small amount of hypo will
indeed prevent oxidization of the silver image but this would have little
to do with mould growth.
>However when I say 'I was told' in relation to mould growth I meant just that
>- not necessarily that I believed it. Some chemicals in the gelatin will
>certainly inhibit growth of various moulds but I have no firm evidence that
>thiosulphate is one of them. It simply amuses me slightly.
Same opinion here.
>In normal years our wet season lasts 12 months, though it has been in short
>supply recently. I think it is probably quite a good thing that my prints are
>somewhat transient in any case!
>
>The gelatin that remains on carbon prints has been very effectively hardened
>as a part of the process which probably makes it less friendly to mould. I've
>not seen it on carbons (yet)
Now that is very interesting. Did you make the carbon prints yourself? Did
you use a hardening bath towards the end of the process? What type?
For the silver prints, did you use a fixer with hardener?
>Do you have any ideas about the cause of the red stain on the platinums? Can
Incomplete removal of the iron salts. Typical of poor quality batch processing.
>it be removed by suitable treatment - perhaps edta? If I had it on any of mine
>I'd give it a try but of course great care is needed with material of
>historical value
The last edition of my platinum book has comments about various restoration
techniques and has an abstract from thesises produced by Mike Ware's V & A
graduate students. In practice, we don't touch historical prints. We
preserve them as much as we can but wet treatments are out of the question.
I have one customer who paid ca. a quarter of a million dollar (then a
world record for a print) for a platinum print (Paul Strand's _Wall
Street_) and I can assure you that we're not touching it.
Luis Nadeau
NADEAUL@NBNET.NB.CA
Fredericton, New Brunswick, Canada
http://www3.nbnet.nb.ca/nadeaul/