Separate stop for film and paper?

[wiseowl]

Many moons ago when I started developing black and white, I was advised to use separate fix for film and paper. I've followed this rule pretty much blindly ever since even though I use the same fixer at the same dilution for both, simply because I can't remember the reason given. Does anyone know if this is really necessary, just good practice or an old wives tale?

I've decided to start using a stop bath, I've used water up till now without any problems, but it strikes me as a good thing to do. Is there any need to keep seperate stop for film and paper, as I have been with fixer?

Cheers

Martin

 

[Donald Miller]

Martin,

I use the same strength mixture of stop for paper and film. The only difference is that with film I dilute this to 1-3 (stop to water). The reason is that I use Pyrocat as my film developer and the dilution alleviates any tendency to pin hole film. This is not only true for Pyrocat but also for the ABC pyro formulation. I discard my film stop bath mixture after each session.

Along the lines of fixer. I use plain hypo (sodium thiosulfate mixed with sodium sulfite) for paper. Some recommend using rapid fixer (ammonium thiosulfate) for film since film has silver iodide as a componant of the emulsion. This ingredient is more difficult to fix. Good luck.

 

[Annemarieke]

I also use separate stop baths for film and paper.

Somebody probably once told me why this is...

My best guess is that the stop bath would become 'polluted' with print developer, which you wouldn't like to end up in your film tanks? And vice versa for film developer on your prints?

Anne Marieke

 

[Alex Hawley]

Hmmm. I've been using the same stop bath for prints and film for a long time. Same goes with fixer. Only very recently, since using pyro and amidol developers, have I started any segregation. I've always used an indicator stop bath which tells you when its exhausted.

Maybe I need to re-think all this.

 

[Dean Williams]

I can certainly see the reason to use different fix for film and paper since (for me at least) they are different in terms of dilution. I have never given stop bath a second thought and use the same for film and paper. Pollution of the stop by the paper developer should be a non issue, since the function of the stop is to kill the developer in the first place. Anyway, I've never had any trouble using the same bath for both film and paper over the past few decades. When it goes bad, it lets me know.
Dean

 

[Adrian Twiss]

Cross contamination may be a valid reason for keeping separate stop baths for film and paper. However I use citric acid as a stop bath (no smell) and it is so cheap to make up that I just throw it away at the end of each session.