Looking over this thread again(I do this on wet Saturday afternoons), does anyone have a formula for how many prints the stop bath can cope with before it needs changing. As far as I can see the usual indicator stop bath is useless for colour work. My stop bath which is Ilfostop and has an indicator designed for B&W work changes colour markedly due to the RA4 developer after a few prints but is presumably still working.
Originally Posted by Tom Duffy
I have tried the "nose" test to detect when it may be exhausted but my stop bath is of the odourless variety so has little odour when fresh but quickly gains an odour which must come from the RA4 developer but may not indicate exhaustion.
For information I process via a Jobo drum and make up about 200cc's of stop, using about 80 to a 100cc's per print but re-mixing it with the stop remaining in the stop container. After processing about 15 prints which are normally 5x7 inch I then throw the stop away and re-fill the stop container with fresh stop.
This may be wasteful or may mean I am economising to a degree that means that the stop is contaminated with developer and dregs of this in the drum is then mixed with blix. I just don't know.