Oh my, it is hard to test just one aspect of a complicated process. You
may remember that all of this started with safelight testing, then led to
questions of complete clearing. It was suggested that paper coated with a
piece of tape covering part of it (to leave a section of "virgin" paper)
could be used to test clearing. When I did this a saw a very faint line,
and assumed I had a clearing problem. WRONG!!!! The tape I was using
"ruffed up" the paper when I removed it, causing most of the the "virgin" /
"chemical" difference. But seeing as I had just bought a few new chemicals
to test..... I coated paper making sure to leave a strait line at the edge
of the coated area (no tape), let it dry (in the dark), cut it into 5
peices, then developed, rinsed, and cleared in differant chemicals.
Results (for me, using Plantinotype paper, Ammonium Citrate developer, half
and half metals) was that 2 oz per gallon of Phosphoric acid showed the
most stain, 8 percent solution of citric acid was the next worst, 1 tbsp of
Sodium Sulfite and 1/2 tspn of EDTA (Bostick and Sullivan, Tetra Sodium)
per liter was perhaps perfect, perhaps I still saw the line, my original 3
tspn of EDTA per liter showed about the same (hard to say it was realy
there), when I increase the after develop wash to 10 minutes (with the
strait EDTA) the line was definately gone.
The differances here a VERY slight, and with changes in time and/or
temperature I suspect that any of these chemicals could completely clear
your print. If you want to test this yourself, use a very "soft" tape, or
just coat the edge of your chemical area very strait.
tomf2468@pipeline.com