Pure silver is very reactive. With the kallitype process, the metallic
silver is "naked" and has little protection, unless it is toned, in
which case it is no longer a true kallitype print.
Modern silver bromide prints have a full emulsion and the silver does
benefit from a certain level of protection from the gelatin coating.
The reason why Galerie paper felt like jello was because of this extra
gel coating. Back in the 70s I was one of the "beta testers" and
consultants on that paper, even before it had a name.
A platinum image is permanent, but it is a strong catalyst and can
affect, even destroy cellulose. A platinum print is almost like an
organic living thing. There have been graduate theses on this subject
recently in France and in the UK and these will be discussed in the
upcoming 3rd revision of my book on platinum printing (end of June I
hope)
Luis Nadeau
Box 7, Site 4, RR4, Fredericton, NB
CANADA E3B 4X5
FAX: (506)450-2718; Hamcall: VE9LN