View Full Version : Wash aid components

Fred Braakman
18-Sep-2006, 19:32
Since hypo clearing agent is not very stable, and can only be used for one printing session, I want to make my own from scratch, rather than buy concentrate. Is sodium sulfite the only component? What concentration is hypo remover usually used at?


Donald Qualls
18-Sep-2006, 21:49
Most commercial wash aids are a mixture of sodium sulfite and sodium bisulfite, likely proportioned to give neutral pH. Plain sulfite works fine, though, and will leave the emulsion in a slightly alkaline state which can further enhance the washing rate (especially important for fiber prints). I use 20 g/L sodium sulfite in filtered (ion exchange filter, made for drinking water) or distilled water, nothing else, and discard after one session. Takes only a couple minutes to mix the sulfite into the water at room temperature; less time than required for the hypo crystals to dissolve for my fixer.

Doremus Scudder
19-Sep-2006, 01:47
Here is a formula that supposedly is similar to Kodak Hypo-Clearing Agent:

Hypo Clearing Agent

Water 1 Liter
Sodium Sulfite 20 g.
Sodium Bisulfite/Metabis. 0.2 g

This works out to roughly one Tablespoon of sodium sulfite plus a pinch of bisulfite of metabisulfite per liter. While I am a stickler for accuracy when mixing most developers from scratch, the spoon recipe for hypo-clear is more than accurate enough and saves me from having to drag out the scales.

The sodium bisulfite/metabisulfite is only in the formula to lower the ph to 7-7.5 to prevent softening of the film. I often use just the sulfite, since it works just as well, and most modern films are pre-hardened anyway.

Note: A stock solution can be made by adding ten times the dry ingredients to 1 liter water. This is then diluted 1:9 for use. However, I find one-shot spoon recipe use to be easiest.