A Tutorial Paper: Photographic Gelatin and Synthetic Colloids for Emulsion Use

Abstract

The natural colloid, gelatin, has been used as the principal support medium for silver halides coated onto various film and paper bases for almost a hundred years. Most users of photographic materials think of gelatin as a physical support for the sensitive materials; hence it would seem simple to replace it with a purer synthetic material of more predictable properties. However, gelatin has a dozen or more specific functions, some of which are still incompletely understood. Although photographic gelatin is a composite of many varying entities, it is made with reasonable uniformity and purity; the chemical industry finds it hard to produce a synthetic colloid which is so reproducible and so low in photographically active impurities. The few substitutes which have reached the market in the form of photographic sensitized materials have limited application, and in most cases, have been withdrawn from production due to unexpected deficiencies. Several international conferences have been held in recent years to discuss the possible improvements in photographic gelatin, and to try to standardize methods of testing.