Subclass 1/053: Photosensitive materials (photosensitive materials for multicolour processes G03C 7/00; for diffusion transfer processes G03C 8/00; photosensitive glass C03C 4/04) Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein (catalytic amounts of silver halide in dry silver systems G03C 1/498) with macromolecular additives; with layer-forming substances Polymers obtained by reactions only involving carbon-to-carbon unsaturated bonds, e.g. vinyl polymers