Appendix D: Chemical Formulae

Most proprietary forms of developer (Xtol, T-Max, etc.) do not have published formulae. They are only sold as ready-mixed concentrated solutions or occasionally as powders. However, the table below gives some well-established developers you can prepare yourself at relatively low cost from their constituent chemicals († = handle with special care).


Chemical When formula quotes weight for And the only available form is Multiply weight by
Sodium carbonate Anhydrous or desiccated Monohydrate or H2O 1.2
Sodium carbonate Anhydrous or desiccated Crystalline or decahydrate (10H2O) 2.7
Sodium sulfite Anhydrous or desiccated Crystalline/heptahydrate (7H2O) 2
Sodium thiosulfate Crystalline/ pentahydrate ...

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