Quote Originally Posted by Michael R 1974 View Post
Regarding F-5/F-6, again, these are hardening Na Thiosulfate fixers. The type of hardener also makes a difference. Still, the discussion in Haist regarding fixer pH and washing (spread throughout the fixation and washing chapters) seems inconclusive. There are parts indicating the washing of gelatin is improved as fixer pH is raised to the isoelectric point (still acid), increasing fixer pH far above the isoelectric point of gelatin may actually retard gelatin washing, the rate of gelatin washing was not materially different for a chrome alum hardening fixer pH 3 and F-24, etc. Then there's the paper base with FB papers - the rate of paper washing is the same within a fixation pH range, the rate of paper washing is not materially affected by fixer pH, the rate of paper washing is improved with swelling when an alkaline bath is used after fixation, etc.
I believe that alkaline fixers swell gelatine faster and therefore allow faster fixation to archival standards. This means the paper needs to spend less time in fixer and therefore the paper base picks up less Thiosulfate which in turn helps during washing. Contrary to what you wrote multiple times I believe that gelatin is least swollen at its isoelectric point, therefore raising pH above that point would increase fixing and washing rate.
Quote Originally Posted by Michael R 1974 View Post
Regarding Anchell/Troop, I would not assume anything actually. Absolutely no evidence is presented to support any of the voluminous conclusions the authors make regarding a myriad of materials and chemicals. There are also plenty of incorrect statements, and conclusions I don't agree with. Sorry but I can't take everything Troop says at face value, and there are clear biases in those books.
Neither Anchell nor Troop ever developed an emulsion, therefore they may not be authorities in that regard. As much as the comments on T-grain emulsion and photographic emulsions may contain erroneous, opinionated or incorrect statements, I would consider his chapters on developers and fixers sound. If one sells fixer recipes to Formulary, he better be on top of this stuff as there is little room for snake oil in the analog market. Neither author owes us data charts or lab notes from when they tested and formulated fixers, and screaming "Their books are *&$!" will rather drive them away from us (as it just so happens, Bill Troop hasn't been on APUG for ages) than make them give us their privately and at their own expense obtained data records.