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).
Substitutions
| 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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