I posted a question a couple of weeks ago about the fairly subtle amount of stain in my HP5+ developed in PMK standard concentration. I had expected more. I decided to try using a generous amount of developer, and I noticed that when I developed a single film in 1 Litre of PMK, the developer after use was not as coloured as usual, and I got less stain. Then I tried one film in 500mL and got more colour in the used developer and more stain.(posted 8494 days ago)Then I remember reading somewhere that the oxidation of PMK was mainly caused by development, not contact with air. So if the desirable stain in the film is caused by oxidised developer, then using less volume should give more stain. So next I used 250mL for one film and the developer came out darker than before. The image stain was about the same as for the 500mL test. I read in Anchell + Troop that 500mL is necessary to be sure that you're getting the full benefit of the developer. This is different advice to that given in Gordon Hutchings's book. I was curious whether my 250mL was exhausted at the end of the first roll, so I used the used developer to develop another roll of HP5+. I gave it 20 minutes instead of 12 to give it a chance but the film came out absolutely blank. So maybe 250mL of PMK is *totally* used up in doing one film. I suppose it means that development time over my 12 min (20c) would not give any significant further development (not that my vigorous negatives needed any more- actually they could have done with a fraction less). I exposed some zone_1 frames on the film and it shows an EI of 160 or 200 (Nikon F100 meter, which is probably my most accurate meter, and most accurate shutter speeds). Next test: will 500mL give me a higher EI?
The only thing I'm doing differently to most other people is that I'm using Agfa FX-Universal alkaline fixer because in Australia TF-4 is not available. It smells slightly of ammonia, fixes fast, and is fairly cheap. It is used primarily for colour processing, but several people have recommended it for B+W. I don't suppose it might have something in it which would reduce the PMK stain, would it?