Variation of a pyro developer with acetone.
| Ingredient | Quantity | |
|---|---|---|
| Potassium metabisulphite | 3.3 | grams |
| Pyrogallol | 60 | grams |
| Sodium sulphite anhydrous | 150 | grams |
| Water to make | 1 | liter |
| Mix chemicals in order. | ||
For tank use, mix 12.5 mililiters stock solution with 0.58 liters of water and 31 mililiters acetone. Develop for 25–35 minutes at 21°C.
For tray use, mix 20 mililiters stock solution with 0.28 liters of water and 6.2 mililiters acetone. Develop for 4–7 minutes at 18.5°C.
As a rule, contrast and density may be increased by decreasing the recommended amount of water to dilute the stock solution by 50%–66%. Softer negatives can be obtained by using 50%–100% more water than is specified for normal results.