I have kept Ammonium Dichromate (bichromate) in a clear glass jar that I
kept with my gum printing kit in a cardboard box that was often open but up
on a shelf with the flaps folded down when not in use (not light tight). The
box was stored in strong sun light. That solution was used off and on for 30
years. When I finally mixed up a fresh batch there seemed to be no change in
my exposures. My experience seems to indicate that on a practical basis The
solution sensitizes the gum or gelatine but doesn't noticably degrade in a
water solution. I only recently used up my old AB crystals that have been in
a light brown jar since I aquired them in the late sixties. The new crystal
AB works the same as the old.
Jack
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Received on Wed Nov 9 17:15:13 2005
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