As my pt/pd prints dry, a dusty white precipitate forms on the surface of the
paper. Some of the deposit can be removed by lightly wiping the print, more
can be removed by dabbing with a gum eraser, and neither of these methods is
satisfactory since they damage the print surface (though almost imperceptibly)
and don't solve the problem (some of the precipitate appears tohave formed just
below the top layer of paper fibers).
I print on Arches Platine, develop in potasssium oxalate with sodium dichromate
as a contrast agent, and clear in a 1:2 solution of Kodak Hypo-clear. The
prints are washed in an archival washer for @45 minutes.
I've tried rinsing the print between each step to no avail. I've also tried to
re-wash the prints after drying , but with only partial success (after more
than two washes, the paper fibers appear to begin separating).
The municipal water supply here is notoriously "hard"; faucets and shower doors
have lots of mineral deposits. I could mix developer and clearing solutions
with water processed through a small reverse osmosis system (today's project),
but would still need to rinse and wash with tap water.
Though it's hard to be sure, I believe that on darker areas of the prints a
slight whitish cast can be detected before the prints go into the washer.
Any ideas? Thanks in advance.
Tom Hawkins