
Originally Posted by
Doremus Scudder
John,
Personally, I've always been skeptical of Heico Perma Wash and its capacity claims. "If it seems too good to be true..."
Kodak had the world's top photographic chemistry R&D labs for decades. The best they (and Ilford) could come up with for a wash aid was a sodium sulfite solution with a bit of pH adjustment (usually in the form of bisulfite/metabisulfite) and chelating agents, etc.
As far as logistics go, I have a couple comments. First I do fine with two liters of solution for 16x20 prints using Paterson 16x20 trays, which are oversized and pretty deep (that's for every solution in the process; developer, stop, fix one and two, and the wash aid). I'll wager you can get by with two liters of wash aid instead of a whole gallon, which is definitely overkill for five 16x20 prints.
Second, I second the suggestion to simply mix your own wash aid one-session using raw chemicals. If your tap water doesn't contain a lot of dissolved minerals, then a Tablespoon of sodium sulfite and a generous pinch of sodium bisulfite per liter is all you need. If you can get by using just two liters of solution then your expenditure is just two Tbsp. sulfite and a bit of bisulfite per session.
With a water rinse before the wash aid (recommended!), then the capacity for this mix is, like the Kodak Hypo Clearing Agent, 200 8x10s per gallon, or roughly 50 8x10s per liter (half that without the rinse before treatment in wash aid). That means you could get 25 16x20s from two liters of solution if you wanted. Still, it would likely be cheap enough that you could discard the solution every session unless you planned on printing again the following day, in which case it could be saved for use in the second session. You don't want to store the working solution for more than a couple of days since it both oxidizes and loses activity and tends to grow bacterial slime.
Hope this helps,
Doremus
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