Plain hypo bath as fixer?

DavidBrunell · Dec 24, 2012

I just realized I have been using a "plain hypo" bath of sodium thiosulfate as a fixer for my last 20 FB prints. Will this be OK or should I re-fix in a different fixer solution?

Gerald C Koch · Dec 24, 2012

Should be OK. But in the future a "plain hypo" fixer also contains sodium sulfite which makes it keep longer without sulfurizing from acid carryover from the stop bath.

DavidBrunell · Dec 24, 2012

Thank you Gerald. It may have? Labeled Hypo by Zone VI...But I am erroring on the side of caution and want to make sure.

David Lyga · Dec 26, 2012

Gerald, I also use plain sodium thiosulfate (penta, usually) and I find it works fine. But, if I use a weak stop bath (1%) and change it frequently, do you still recommend the necessity of the sulfite, even though I do not usually reuse the fixer after the session? (I use small liquid quantities for prints so that I can discard without wasting.) No problems yet. - David Lyga

Gerald C Koch · Dec 28, 2012

David Lyga said:
Gerald, I also use plain sodium thiosulfate (penta, usually) and I find it works fine. But, if I use a weak stop bath (1%) and change it frequently, do you still recommend the necessity of the sulfite, even though I do not usually reuse the fixer after the session? (I use small liquid quantities for prints so that I can discard without wasting.) No problems yet. - David Lyga

If you have not seen any sulfurization with your process then I wouldn't worry. However a 3% acetic acid stop might cause problems.

A good "plain" hypo bath would be 240 g sodium thiosulfate pentahydrate and 15 g sodium sulfite to make 1 liter of fixer.

juan · Dec 28, 2012

It's been more than 20-years, but I think Hypo from Zone VI was plain hypo, while fixer with other ingredients was labeled Zone VI Fixer.
juan

cliveh · Dec 28, 2012

Nothing wrong with sodium thiosulfate, but fixation may take a little longer.

George Collier · Dec 28, 2012

Juan is correct about the two products, they sold plain hypo for use with selenium (and maybe other types of) toning and fixer for actual fixing of film and paper.
I believe some of the other components in a fixer bath also extend the life of the solution, like keeping dissolved silver salts in solution, preventing precipitates.

Maybe PE will pick up this thread and give us a better explanation.

Plain hypo bath as fixer?

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