Impact of Calcium and Methionine on the Variability of a Sulphur and Gold Sensitization on a Bromoiodide Emulsion

Abstract

Chemical sensitization uniformity requires tight batch-to-batch control of components of gelatin as well as the non-gelatin components that are present. Chemical sensitization sensitivity to variations in methionine and calcium was examined using a bromoiodide emulsion at fixed levels of sulphur and gold sensitizer. Hydrogen peroxide treatment of gelatin was used to generate a series of partially oxidized gelatins with varying methionine content. Calcium variation was examined by choosing gelatin with known natural variations in calcium and by addition of calcium salts to deionized gelatins. Sensitometric changes were seen as a function of both calcium and methionine variation. Results indicate that methionine and calcium must be carefully controlled to minimize photographic change.