quick, 10 to 30 seconds recommended.
Water stop: Maintains an alkaline or neutral fix. Extended
single or multiple rinses recommended.
The acid stop and fix will render the developer inactive.
A protracted or multiple water stop will wash the film or
paper free of developer; developer which otherwise would
be active in an alkaline stop.
My method of processing, which is similar to the rotary film
and print method, uses no stop what so ever. All chemistry
is used very dilute one-shot. Dan
I am kinda partial to baths---maybe it is me being in touch with the my feminine side---so stop baths NEVER!!!
But on film and paper sure always have so why not "stop" The only time I don't use stop baths is when I shoot a film that recommends against it like Efke/Adox.
Hey Ansel Adams recommends it---good enuff for him good enuff for me :)
Most developers require far higher pH to work than any alkaline fixer has. So a quick wash in water, followed by an alkaline (buffered) fixer would reduce the pH to below the threshold for the developer just as efficiently as an acidic fixer would.
The only exception is Amidol, but that works even in slightly acidic conditions so with a quick stop and into the fixer it makes no difference if the stop is acidic or water.
acid stop bath, letting it drain adequately to carry over as little as possible into the fix; there has never been a problem.
The purpose of a stop bath is to quickly and completely stop the development process. It makes development predictable. A weak acid solution, like 2 percent acetic acid, does that admirably well. But I have always used a simple water rinse - usually a quick rise followed by a second rinse of about 30 seconds. It works fine, and I'm used to doing things that way. But a simple water rinse may not be all that certain for everyone.
Hmmm ... Thanks for all the responses. I'm not sure I have a "definitive" answer. Some amazing printers that use stop solution and some amazing printers that use water ... what to do, what to do ...
Just to clarify as well, I was posing the question with respect to film development not paper. Thanks again.
There was some research that suggested that sodium thiosulphate, ('acid fix') is inadequate for current emulsions and that ammonium thiosulphate is best. Further, alkaline solutions wash out much more efficiently than acid. I've been using a water stop for film for many years, (6 full changes of water) and an alkaline fixer. I ran tests a couple of years ago and it looked like the film washed to 'archival' in 2.5 minutes - I use 20 min though! The continued developer action in the water rinse is taken care of in your development tests, as long as you remain absolutely consistent in your technique. For printing, I use an acid stop but add a water rinse between stop and fix.