| Water | 9 ounces |
| Sulphite of sodium | 3 1/2 ounces |
| Diogen | 7 drachms |
| Carbonate of potassium | 4 1/2 ounces |
For normal exposure take 4 drachms of this solution; dilute with 2 ounces, 1 drachm of water, and add 2 drops bromide of potassium, 10 per cent solution.
Ortol Developer.
| I.— | Water | 1 ounce |
|---|
| Metabisulphite of potassium | 4 grains |
| Ortol | 8 grains |
| II.— | Water | 1 ounce |
|---|
| Sulphite of sodium | 48 grains |
| Carbonate of potassium | 16 grains |
| Carbonate of sodium | 32 grains |
For use take equal parts I and II, and an equal bulk of water.
Metacarbol Developer.—
| Metacarbol | 25 grains |
| Sulphite of soda, crystals | 100 grains |
| Caustic soda | 50 grains |
| Water | 10 ounces |
Dissolve the metacarbol in water, then add the sulphite, and when dissolved add the caustic soda and filter.
Developing Powders.
| By weight |
|---|
| I.— | Pyrogallol | 0.3 parts |
|---|
| Sodium bisulphite | 1.2 parts |
| Sodium carbonate | 1.2 parts |
| II.— | Eikonogen | 1.1 parts |
|---|
| Sodium sulphite | 2.4 parts |
| Potassium carbonate | 1.5 parts |
| III.— | Hydroquinone | 0.6 parts |
|---|
| Sodium sulphite | 3.4 parts |
| Potassium bromide | 0.3 parts |
| Sodium carbonate | 7.0 parts |