I believe the pH of the standard working solution (fresh) is somewhere between 2 and 3. If one were to mix it at half strength (say 8ml/l instead of 16ml/l), does that increase the pH significantly? I think total acidity would decrease, but not sure how much the pH would increase. Actually, is a half-strength mix of Kodak stop bath even still an effective stop bath? Working on some new experiments with PMK and I can't find all my old notes. Hutchings recommended the "ideal" stop bath pH of 4.5 in his book, but frankly I'm not sure how much of all that is still valid. Further, Wimberley always recommended a standard stop bath be used with his various WD2 developers even though they use a carbonate alkali. Which reminds me of another question - is it really necessary to avoid acid stop baths with carbonate-driven developers? Or does it really depend on the pH of the particular developer?