What is the role of Sodium Metabisulfite in this formula for Washing Aid ?
Water 750 ml
Sodium Sulfite (anhydrous) 100 g
Sodium Metabisulfite 25 g
Cold water to make 1L
What is the role of Sodium Metabisulfite in this formula for Washing Aid ?
Water 750 ml
Sodium Sulfite (anhydrous) 100 g
Sodium Metabisulfite 25 g
Cold water to make 1L
Last edited by Ken Lee; 15-May-2006 at 17:31.
The Sodium Metabisulfite acts as a buffer for the Sodium Sulfite.
Sounds like it is there to promote longer shelf-life, no ?
So if I were to mix up and use some fresh solution, using only Sodium Sulfite - and then toss it - would there be no need for the buffering agent ?
To quote from David Vestal's "The Art of B&W Enlarging";
"A test done using home-mixed 2-percent sodium sulfite solution as the washing aid suggests that it's about 80 percent as effective as Kodak Hypo Clearing Agent; a longer wash should get the prints as clean."
Ken,
I have used just sod sulfite for many years as a subsitute for HCA. I always toss it after the darkroom session. It is too cheap to save and risk it not working.
lee\c
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