Plain hypo bath as fixer?

[DavidBrunell]

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]

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]

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]

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]

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]

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]

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

 

[George Collier]

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.