Alkaline Fixer & Acid Stop Bath?

pawlowski6132 · Nov 11, 2010

I want to use TF-4 as my fixer when developing AZO developed in Amidol. I am under the impression that a "water stop" is not strong enough and really need an acidic stop.

1. Is this true?
2. Can I use an acid stop AND an alkaline fixer?

thanx in advance.

Joe

nworth · Nov 11, 2010

TF-4 is well enough buffered so that you can use the common acid stop baths, like 2 percent acetic acid, with it. The small amount of acid carryover will not affect the fixer. People will argue forever about the need for an acid stop bath. Certainly a running water rinse will do the job. If you use a tray of water, it becomes weak developer in a very short time. I happen to prefer a stop bath. I think it helps to preserve the life of the fixer, and I think it helps to prevent stains.

juan · Nov 11, 2010

When using amidol and Azo, I mix a little citric acid with water for stop. It smells much less terrible than the acetic acid. I've had no problems with alkaline fixers - TF2 or TF4.
juan

Photo Engineer · Nov 11, 2010

I have run TF-4 with a stop and a water rinse testing varying levels of running water and still water in the rinse. I have gotten various levels of fog in standing rinses even with a fresh charge of water in the tray, or with a low rate of running water. I have never gotten fog when I use a stop bath and I have never hurt the TF-4 or print by using a stop. This all refers to prints on FB or RC. The fast rate of development is the issue here combined with alkali and a silver halide solvent. That can fog paper emulsions.

So, my workflow for prints using TF-4 always includes a stop.

PE

Dan Henderson · Nov 11, 2010

I stopped using acid stop bath when I switched to TF4, then TF5, for both film and paper. Any development that continues after the film or print is placed in a plain water stop bath is baked into the the time I have determined optimal for film development and test strips for print development. The only time I use stop bath is when I am lith printing by inspection and need to immediately stop development. Even then I give my prints a 30 second water bath before they go into the fixer. I really don't know if there is any science behind this, but it just seems like a good thing to do, and can do no harm.

Although after reading Ron's post above (which was apparently made while I was composing mine) I may start using a weak citric acid stop bath.

hpulley · Nov 11, 2010

I'm sure you guys already know this but just in case, Ilfostop is a low odor citric acid stop bath.

Ian Grant · Nov 11, 2010

Just beware the UK manufactured alkali fixer where the manufacturer says you must use his alkali stop bath .

I'm not a proponent of Alkali fixers but I've seen the dichroic fogging when no stop bath is used first with an alkaline fixer, and Ron (PE) has always been very clear in his recommendations of using a stop bath before an alkali fixer.

Ron designed these fixers so if he says a stop bath is important then in this case I have to totally agree, but that agreement is based on experience to.

Ian

nworth · Nov 11, 2010

Ian Grant said:
Just beware the UK manufactured alkali fixer where the manufacturer says you must use his alkali stop bath .

I...
Ian

I'm not sure what an "alkali stop bath" would be. I would stay away from any fixer that gave those instructions. They probably don't know what they are talking about.

Vlad Soare · Nov 12, 2010

I'm not sure what an "alkali stop bath" would be.

It's probably a strong restrainer of some sort. A high concentration of potassium bromide or benzotriazole would probably work. Maybe also a bit of sulfite/borax/bicarbonate/whatever to increase the pH a little. But I'm just speculating here. I haven't yet seen such a stop bath myself, nor found any specific formulae.

Photo Engineer · Nov 12, 2010

You guys are right on. An alkaline stop can be made by either method that Vlad proposes and both have problems.

PE

Alkaline Fixer & Acid Stop Bath?

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