Reusing stop bath? (Kodak max stop)

[Kozhe]

Hi everybody!

I guess this is one of those silly little questions everybody has to ask once!

I´m using a chemical stop bath for the first time and mixed Kodak max stop 1:15, 40mm on 650mm of water. Can I store and reuse this thing or should I throw it and make a fresh new mix again next time?

Thanks!

 

[Chris101]

I don't use stop for film, but if I did I would use one with an indicator in it so I could tell when it's spent. The idea for stop bath is that making the emulsion acidic will 'stop' the action of the developer. As long as the stop bath is acidic (pH below 7) then it's good. Not having an indicator (turns purple when it's no longer acidic) means that you will need to test it occasionally, but it should be good for many uses.

 

[Kozhe]

Thanks Chris! The stop bath I´m using has an indicator, but I thought it was more paper oriented and only visible with red security light.

 

[JohnTF]

I also do not use stop bath for film, and for paper I would consider some of the odorless formulas, -- and I do not reuse stop baths.

OTOH, I have been getting free acetic acid for years. ;-)

Regards, John

 

[bsdunek]

I also only use a water bath after developer for film. I love the smell of acetic acid stop in the darkroom when I'm printing. As someone said, the smells in the darkroom are the smell of creativity!

 

[Michael P.]

Thanks Chris! The stop bath I´m using has an indicator, but I thought it was more paper oriented and only visible with red security light.

It's yellow when it's fresh. When it's exhausted It turns purple and looks black under a safelight.

 

[Tom A]

I dont use stop bath for film either. Modern emulsions are usually quite thin and the "chock" of having the acetic acid coming contact with the emulsion can cause pin-holes. Just use 2 changes of water - agitate the water and dump it.
If you use stop bath - regard it as a once only bath. If you keep reusing it, there is a fair chance of stuff accumulating in it and sticking to the film.
For paper I do use indicator stop bath and change it frequently (10-12 11x14 fiber based prints - then dump it). It also depends on your paper developer - using the old defender formula - it turns purple after 3-4 prints!

 

[JohnTF]

I dont use stop bath for film either. Modern emulsions are usually quite thin and the "chock" of having the acetic acid coming contact with the emulsion can cause pin-holes. Just use 2 changes of water - agitate the water and dump it.
If you use stop bath - regard it as a once only bath. If you keep reusing it, there is a fair chance of stuff accumulating in it and sticking to the film.
For paper I do use indicator stop bath and change it frequently (10-12 11x14 fiber based prints - then dump it). It also depends on your paper developer - using the old defender formula - it turns purple after 3-4 prints!

Must be seriously alkaline? I have played around a few times adjusting the pH up with results that seemed to remove the restrainers and change a fine grain high contrast print in to a normal contrast but very grainy print.


John

 

[BillBingham2]

Never reuse stop bath that has had paper in it with film.

While I had access to free stop bath for many years, I just used water, same temperature as the developer and fixer. Some times I would use it but water was just easier.

B2 (;->

 

[JohnTF]

I did use it most recently for RA4 for the second slot of the processor.

John

 

[dufffader]

I am one of the rare RFFers that use stop bath it seems. I do recycle them. The indicator will turn purplish after many many cycles. And when it turns colour, it is very obvious, no need for any special assistance to see it, unless colour blind of course. I don't even remember the last time I bought a new bottle of SB!

 

[ruby.monkey]

Wouldn't dust show as black spots on the negative scan, and therefore white when you invert it?

 

[Roger Hicks]

Although I no longer use stop bath with film, I have to say that during the decades when I did, I never encountered pinholes.

Cheers,

R.

 

[Tom A]

Must be seriously alkaline? I have played around a few times adjusting the pH up with results that seemed to remove the restrainers and change a fine grain high contrast print in to a normal contrast but very grainy print.


John

The old Defender uses almost 300 grams of Carbonate in 3000 ml of developer!!!!! It is not for every print - but with "old" style fiber based paper it is stunning. Larry Clark and Eugeen Smith used it. It does give blacks that are something else!

 

[JohnTF]

The old Defender uses almost 300 grams of Carbonate in 3000 ml of developer!!!!! It is not for every print - but with "old" style fiber based paper it is stunning. Larry Clark and Eugeen Smith used it. It does give blacks that are something else!

Though I have training in the sciences, I was a bit jealous when a former student saw me in a local pub, telling me his PhD in Fine Arts Photography included an excellent course in photo chemistry, enabling him to customize numbers of formulas.

I am more of a cook book chemist in the darkroom, adding a little spice occasionally.

John