GB377411A - Improvements in process of preparing coloured photographic and cinematographic pictures - Google Patents

Abstract

377,411. Colour photography and kinematography. DASSONVILLE, L. J., 35, Avenue Paul de Jaer, Brussels. July 11, 1931, No. 19999. Convention date, July 16, 1930. [Class 98 (ii).] In the production of coloured photographic positives by successive exposures, from the same side, under two complementary negatives, of a layer sensitized by a silver salt and thereafter resensitized by a salt of another metal ; after printing, developing, and fixing the silver image the layer is resensitized by an iron salt adapted to discolour the silver image and render it capable of being mordanted, and the second image is printed and developed in colour after which the first image is dyed through the second. Thus, an orange - red negative is printed upon an ordinary silver-sensitized film and, after developing and fixing the silver image, the film is resensitized with a solution of ferric chloride containing oxalic acid, dried and exposed under the blue-green negative. After developing with potassium ferricyanide, the film is washed and immersed in a mordant bath of potassium iodide and is then passed through a bath of orange-red aniline dye and washed with acidulated water. The second image may be printed from a positive and developed with potassium ferrocyanide. For a three-colour result, the third component is superimposed by mechanical printing. Instead of ferric chloride, the oxalate, tartrate, or citrate may be employed. The Specification as open to inspection under Sect. 91 (3) (a) states that salts of other metals, e.g. cobalt, cerium, or manganese may be used for resensitizing. This subject-matter does not appear in the Specification as accepted.