toner
Kodak T-7a sulfide sepia toner
Handle chemistry safely
Wear gloves and eye protection, work with good ventilation, and read the supplier’s safety data sheet before use. Hazard information here is a summary, not a replacement for it. Dispose of all photographic chemistry correctly, in line with local laws and your local authority’s guidance. Never mix waste solutions, and check the supplier’s safety data sheet before disposing of anything.
Ingredients
| Potassium ferricyanide | 75 g |
| Potassium bromide | 75 g |
| Potassium oxalate monohydrate | 195 g |
| Acetic acid (28%) | 40 mL |
| Sodium sulfide (anhydrous) | 45 g |
| Water to make | A: 2.0 L water; B: 500 mL water |
Notes
Two-step bleach-and-redevelop sepia. Use the bleach stock 1+1 with water until only a faint image remains, rinse well, then redevelop in 125 mL of the sulfide stock made up to 1 L until detail returns. Rinse, harden and wash. Kodak warns against trays with exposed iron. Sodium sulfide gives off hydrogen sulfide, so work with good ventilation.
Source
Processing Chemicals and Formulas for Black-and-White Photography (Kodak Publication J-1), 7th edition, Eastman Kodak Company (1977), p. 47
Amounts as published. Chemical forms (anhydrous, monohydrate and so on) change the weights, so match the form listed.