Quote Originally Posted by john_s View Post
The only essential ingredient in a fixer is thiosulphate. All the rest is secondary, being preservative (primarily) and pH adjusting, and perhaps hardening. Rapid fixers are ammonium thiosulphate. If they are acidic they smell of SO2. If they are alkaline they smell of ammonia. If they are close to neutral (i.e. between acidic and alkaline) they have minimal smell. If you use materials from mainstream companies you don't need hardening, so use something like Kodak Flexicolor Fixer (pH=6.5) which is cheap, rapid and not very smelly. It's sold for color procesing but is totally functional for b+w fil and paper.

I said most of this in an earlier post with one notable exception. Most commercial fixes are not a single ingredient. And, they ALL contain Sulfite while most contain Ammonia. Therefore there is odor at either end of the pH spectrum, namely 4.5 or 8.0 approximately. The ideal is between about 5.5 and 6.8.


AFAIK, both Tmax and Trix use the same gelatin and the same hardener and therefore should respond about the same to temperature variations. Kodak has processes for these up to 90 degrees IIRC. Sometimes, very soft water coupled with extreme changes in temperature may cause problems, but it should be about the same for either film all other things being equal.