Removal of Pyrocat Stain....

[Patrick Robert James]

I rarely start any threads here, but I've run into a problem that I can't find a solution for. I have some recent negs developed in pyrocat and I want to remove the stain and redevelop them since the stain is streaky from some, ahem, past date Pyrocat. I've tried soaking one in a saturated solution of Sodium Sulfite and that didn't do squat. I also bleached one in ferri/bromide and it did bleach, except for of course the stain.

Anyone know how to eliminate the stain from Pyrocat?

This has turned into an academic exercise for me since the negs might not be any good anyway, but in all my searching I couldn't find a solution to the problem. I have been curious about his for years though since I have an old neg with a streak on it. In all that time I've never run across a solution. I thought I'd ask...

Anyone have a clue?

 

[Andrew O'Neill]

From Henley's 20th Century Formulas, Recipes, and Processes:

Proto-sulphate of iron 3 ounces
Alum 1 ounce
Citric acid 1 ounce
Water 20 ounces

After clearing pyro stain from the negative, it should be washed thoroughly.

 

[jim appleyard]

Proto-sulphate of iron. I don't know this, what is it?

 

[removed account4]

no clue ! but mr g00000gle says
" protosulphate of iron or ferrous sulphate (FeSO4), commercially known as green vitriol. "

when you use the googlfu
you get cheelated iron fertilizers too ...

 

[Patrick Robert James]

From Henley's 20th Century Formulas, Recipes, and Processes:

Proto-sulphate of iron 3 ounces
Alum 1 ounce
Citric acid 1 ounce
Water 20 ounces

After clearing pyro stain from the negative, it should be washed thoroughly.

Thanks Andrew. I appreciate it.

Looks like it is Ferrous Sulphate. Photographers' Formulary is out of it right now of course....