BTW: I prefer using chrome oxide green directly from the tube instead of waiting
years for the decomposition of dichromate... ;-)
Thanks, Pete, for this testing. It gives a good idea of what is going on.
Sulfuric acid really is a mean thing: You think you worked carefully and then
the holes in your clothes always show up after the washing... Potassium alum
isn't that good either: paper conservators don't like it as during aging it can
destroy the paper fibres. (Right Bas?). So long washing might be the best, but
most wet dichromate images are very delicate and I don't want to stand 12 hours
next to the tray and keep my print from sinking to the ground or touching others
or watching for air bells...
If we really are concerned about the archival properties of our dichromate
prints, we also should think about a (simple) method to test for residual
clearing bath after the washing. What would be the lowest concentration allowed?
Is there any information about the speed of the decomposition reaction of paper
in relation to its clearing bath content (sulfuric acid, alum, bisulfite...)?
Or: could one of our chemists please explain, how to neutralize the clearing
baths and probably create an alkaline reserve in the paper?
Klaus Pollmeier