Improvements relating to the Reproduction of Images on Glass, Ceramic, Metallic or other Surfaces

17,432. Ling, A. R., Rendle, T., and Colbrook, B. W. Aug. 19. Ornamenting by photography; chromo-gelatine and like processes.-Improvements are described on the process described in Specification No. 24,214, A.D. 1907. Nitrocellulose or collodion can be dispensed with in the sensitizing-film by using ground glass or other roughened and non-absorbent surface for the support. The sensitizing-film contains essentially invert-sugar, honey, or other carbohydrate or carbohydrate mixture, together with a volatile solvent of the bichromate and carbohydrate. Bicbromates of the alkalies or alkaline-earth metals or of copper and iron can be used ; and as solvents alcohol, wood spirit, ether, ethyl acetate, or acetone are suitable. Polychromates or chromic acid can be used instead of bichromates, although they are not so serviceable, and glycerine in the place of carbohydrates. Where chromic acid is used, carbohydrates cannot be employed owing to the resulting oxidation that would take place in the presence of chromic acid, and glycerine is then used with acetic acid as solvent. Where acetone is employed as the solvent, glycerine is used owing to the slight solubility of carbohydrates in acetone. After the coated surface has been exposed it is dusted with pigment and washed, and can be varnished or fired as required. The glass may be subjected to sufficient heat to vitrify or fuse the surface and remove its roughened appearance.