This is a cutting reducer for lessening the density of heavy negatives and at the same time increasing their contrast. It is especially valuable for reproduction films to clear the whites.
Solution 1
| Sodium Thiosulfate | 240 g |
| Water to make | 1 L |
Solution 2
| Ferricyanide | 19 g |
| Water to make | 250 ml |
For use, mix one part Solution 2 and fourparts Solution 1 in 32 parts water. Solutions 1 and 2 should be stored separately and mixed immediately before use.
From Ansco Formulas for Black and White Film by GAF, 1948 – Formulas are provided for historical reference. They may not work well with modern films and papers. Some of the chemicals can be dangerous. As with all photographic processes, be careful.
