Improvements in photographic sensitive layers having protective coatings

Abstract

Abstract 450,220. Protective layers for photographic emulsions. GROVES, W. W., 30, Southampton Buildings, Chancery Lane, London.-(I. G. Farbenindustrie Akt.-Ges.; Frankfort-on-Main, Germany) Jan. 10, 1935, No. 889. [Class 98 (ii)] Photographic sensitive emulsion layers are coated with thin protective layers of a natural or artificial resin containing one or more salt forming hydroxyl or carboxyl groups and soluble in alkali, by application to the layers of solutions of the resin in non-aqueous solvents. Dyes or stabilizers for the emulsion may be incorporated in the layers. Suitable natural resins are colophony or shellac As artificial resins, the condensation products of formaldehyde or phenol alcohols with phenols, oxy-, aryloxy-, or alkyloxy - carboxylic acids or phenoxy fatty acids may be used. Artificial resins after-treated with halogen fatty acids, and the condensation products of phenols or phenolcarboxylic acids with aliphatic, aromatic, or heterocyclic aldehydes or thionyl chloride may also be used. In examples, solutions of (1) the artificial resin from phenoxy acetic acid and formaldehyde in alcohol to which diphenylamine as a stabilizer or Naphthol Yellow as a filter dye may be added and (2) colophony dissolved in sodium carbonate, reprecipitated by acid and dissolved in butanol are applied to the emulsion layers of photographic plates or films. Specification 437,386 is referred to.

Inventors

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