Test: shake up the covered jar, open quickly & take a
whiff. If you smell hydrogen sulfide (rotten egg) odor, throw the stuff
out. It makes, I am told, sulfurous acid (or something like that), which
is a silver bleach. And even if you overprint enough originally so you
survive the fixing, it can bleach the print in the hereafter.
I should say I've never seen this in POP (which I've never done), but
have seen it with vandyke brown when we ran out of sodium thiosulphate &
dug up an old, really old, jar from the back of the closet. This doesn't
mean, BTW, that you can't use old crystals -- we're finishing up a
50-pound drum of the stuff at school that probably came in with
Gertrude Kasebier. But some will go. My assistant recently got two bad
pounds in a row from (sorry folks!) Photographer's Formulary. You don't
know how long that jar sat in the store or what it was like to
begin with ......Another day another
post I'll describe my adventures with Kodak "factory sealed" potassium
ferricyanide, but suffice to say, well, what to say?
Caveat emptor or rather,
Caveat POP-er
Judy
PS. Did anyone say POP has to be very much overprinted exactly because it
lightens in the fix? At least that's what I heard from my neighbor who
left POP for cyanotype & no regrets. I wonder, incidentally, if Gini
could take some coated sheets of cyanotype & use them for proofing. Think
that's what the colonials did in Africa & Egypt, no? In fact, you could
take two little bottles -- A & B solution & a foam applicator, and tell
customs it's your cough medicine.
Exposure might be slightly longer than POP, but not so much, and think of
the economy. Of course the paper might not keep well in hot humid climate
-- though maybe you could pack it with calcium carbonate......??? Or go to
Labrador?
Anyway, Gini's description sounds so romantic, it almost makes one
want to travel -- just to develop in the hotel sink!