View Full Version : Progressive contamination of fixer from stop bath
As I was busy in the darkroom this afternoon, I noticed that the paper, being soaked in developper, leaves some developper in the stop bath. This is not a problem. But then, after staying in the stop bath, the paper transits to the fixer, and bring some stop bath in the fixer. After my printing session, I noticed that the fixer had a slight yellowish color whose origin is without doubt the indicator stop bath.
Now, does this stop bath affect either the shelf life of the contaminated fixer and/or the capacity to fix the nominal number of 8x10 sheets of paper ?
Would it make sense to use a short water bath before dipping the paper in the fixer ?
ic-racer
14-Jul-2012, 18:02
There is acetic acid (pure stop bath) already included in some fixers: http://www.digitaltruth.com/products/formulary_tech/03-0146.pdf
Others, like Ilford Hypam have Boric Acid.
Either way, getting weak acid in some fixers should not be a problem.
Not all stop baths and fixers are the same, however. What kind of fixer and stop are you using?
What kind of fixer and stop are you using?
Kodak indicator stop bath, and Kodak Fixer.
I was not aware that acetic acid was present in fixers, and I thank you for this information; I will stop worrying.
Fixer is designed to be used after the stop bath. Contamination is not a concern.
- Leigh
If it concerns you, and if you have the sink space, just add a water bath tray in between the two.
I always let the print drain over the stop bath tray for a minute before putting it in the fixer.
This greatly reduces the carry-over.
- Leigh
Dan Henderson
15-Jul-2012, 17:11
Many people use alkaline fixers such as TF4 or 5. In these cases an acid stop bath is not recommended. I, like many others, use a plain water stop bath. Some people express concern that development continues in the water stop, but if you process your test strips/prints in the water stop, continued development is "baked in."
Heroique
15-Jul-2012, 17:32
I use Kodak indicator stop bath, and Kodak Fixer ... Now, does this stop bath affect either the shelf life of the contaminated fixer and/or the capacity to fix the nominal number of 8x10 sheets of paper?
Also, here’s a helpful sheet (http://www.kodak.com/global/en/professional/support/techPubs/e103cf/e103cf.pdf?id=0.1.16.14.30.14.7.14.16&lc=en
) from Kodak about how many sheets you can fix before the solution is exhausted.
It defines enough conditions to make it generally useful for most people, I think.
Depending on your personal workflow, it could be useful if you keep notes from session to session.
Thanks to all for the information. I guess that the fixer that I use will not be adversely affected by the indicator stop bath that is finding it's way in it.
One thing less to worry about.
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