Pyrocat and acid stop baths

pkr1979 · Jul 8, 2021

Hi all,

Im giving the Tetenal Odorless neutral fixer ago. However, when using this fixer apparently a acid stop bath is mandatory.
Im using Pyrocat-M and as far as I can remember Mr. King recommended to use a acid stop bath at half or quarter the regular strength...

Does anyone have any experience/opinion on if a acid stop bath has to be used at half strength or less with Pyrocat? Or will regular strength be fine without damaging the stain?

Does anyone have any experience/opinion on using neutral fixers with just a water stop bath? As far as I can understand with a neutral fixer the acid stop bath prevents dichroic fog.

Cheers
Peter

Rick A · Jul 8, 2021

I use two 30 second water rinses between developing and fixing with pyro developers. I use EcoPro Clearfix Neutral fixer. You can use stop bath diluted 1+1 from stock solution. Using water in place of stop shortens the life of the fixer.

MattKing · Jul 8, 2021

Rick A said:
You can use stop bath diluted 1+1 from stock solution.

For clarity, and because "stock" can be interpreted in a couple of ways, I think Rick means stop bath further diluted 1 + 1 from the usual working dilution.
And I'm assuming "Mr. King" means Sandy King .

Andrew O'Neill · Jul 8, 2021

I'm not familiar with that fixer. I use Ilford rapid fix with Pyrocat-HD. For stop bath, I usually use diluted vinegar to give me a 1% working solution, or a citric acid bath. I have also used Ilford's indicator stop bath at full strength. Have had no issues.

Raghu Kuvempunagar · Jul 9, 2021

Rick A said:
Using water in place of stop shortens the life of the fixer.

Rick: what does water stopbath do to neutral fixer to shorten the latter's life?

Rick A · Jul 9, 2021

Raghu Kuvempunagar said:
Rick: what does water stopbath do to neutral fixer to shorten the latter's life?

Water does not neutralize the developer,, it merely slows development and the remaining developer is washed off by the fixer and contaminates it. It does this to any fixer, not just neutral fix.

Matt King, you are correct, I meant to say working solution stop bath. ( I claim "old timers" for the brain fart )

john_s · Jul 9, 2021

Rick A said:
....... and the remaining developer is washed off by the fixer and contaminates it. It does this to any fixer, not just neutral fix...... ( I claim "old timers" for the brain fart )

If this is a concern, a water bath can be longer and perhaps use either running water or refresh the water.

pkr1979 · Jul 9, 2021

@Rick A , I expect you never had any dichroic fog then, despite not using acid stop bath in combination with a neutral fixer?

@MattKing , Mr King is Sandy

@Andrew O'Neill , thanks for the feedback.

Rick A · Jul 9, 2021

pkr1979 said:
@Rick A , I expect you never had any dichroic fog then, despite not using acid stop bath in combination with a neutral fixer?
Dichroic fog would result from under fixing either by too short fixing time or spent fixer.

john_s said:

If this is a concern, a water bath can be longer and perhaps use either running water or refresh the water.

Click to expand...

There really is no need to rinse more, chemicals are relatively inexpensive. Do whatever makes you happy.

Lachlan Young · Jul 9, 2021

I think it probably relates to certain less well hardened emulsions (Efke) and the potential for issues going from a developer containing quite a lot of carbonate into an acid stop.

Alan9940 · Jul 9, 2021

I have used a half-strength acid stop without any noticeable issues, though I usually use a couple changes of water. Full disclosure...I don't use a neutral fix; prefer to mix my own F-24.

Vaughn · Jul 9, 2021

Rick A said:
Water does not neutralize the developer,, it merely slows development and the remaining developer is washed off by the fixer and contaminates it. It does this to any fixer, not just neutral fix.

Matt King, you are correct, I meant to say working solution stop bath. ( I claim "old timers" for the brain fart )

So basically, one is concerned with maintaining the acidic level of the fixer. The same amount of the components of the developer will end up in the fix no matter the type of stop or fix. Stop bath does not remove the developer, just neutralizes it. Seems to me the most important aspect is just rinsing the developer off the surface of the film (with water or other stop bath) before going into fixer. The better you do it, the longer the fix lasts.

GLS · Jul 10, 2021

I use a ~ 1% solution of citric acid as stop when developing with Pyrocat-HD. There are no ill effects that I can discern.

pkr1979 · Jul 10, 2021

Thanks for the feedback guys. Im gonna go for half strength

Pyrocat and acid stop baths

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Pyrocat and acid stop baths

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