A non-hardening fixer for films or paper
Water at 52°C /125°F – 500ml (I use boiled water, after cooling, as I live in a very hard water area. Distilled water would work too. This reduces any potential cloudiness in the fixer.
Sodium thiosulphate – 240g
Sodium sulphite – 10g
Citric acid – 22g
Water to make 1 litre.
A non-hardening acid fixer, suitable for use with films or prints and particularly suitable for films developed in pyro, as the lower acidity of this fixer does not adversely affect the pyro stain. It is also suitable for fixing prints that are to be subsequently toned, due to the absence of a hardener.
This formulation uses citric acid instead of sodium bisulphite, as recommended in The Darkroom Cookbook as a way of reducing the sulphur odour. Personally, I still think it smells very strongly of sulphur, especially compared to my standard fixer, Ilford Hypam, but I guess any formulation that uses two sulphur compounds is bound to smell of it.
Use undiluted; approximate time for films 5 minutes at 20°C with intermittent agitation. Prints should be fixed for about the same time, preferably using a two-bath method.