GB991023A - Process for preparing photosensitive elements - Google Patents

Abstract

991,023. Photographic materials. HORIZONS Inc. March 28,1962 [March 30,1961],No. 11938/62. Drawings to Specification. Heading G2C. A method of preparing a photosensitive element comprises: depositing a first layer on a flat support by applying a solution of a bleach-out polymethine dye and a compound R-C-X 3 where R is H, Cl, Bn, I, alkyl, aryl or substituted alkyl or aryl and each X is C1, Br or I; drying the layer to remove the solvent; optionally depositing a barrier layer on the first layer from a solution of a filmforming plastic and drying the same; coating a second layer on either the first or the barrier layer from a solution of a filmthe first but wherein the dye is sensitive to light of a different wavelength; and drying the second layer, the solvents used being chosen so that there is no intermingling of the first and second layers. A further barrier layer of clean plastic may be deposited on the second layer and a third photosensitive layer may be deposited either above the second layer or on the reverse of the support. Preferably there are three photosensitive layers containing yellow, magenta and cyan dyes so that the element yields a full colour reproduction. The materials themselves are described in Specifications 991,021 and 991,022 and the present invention is concerned with an improved method of preparaing the photosensitive element therefrom to improve the reproducibility of photosensitivity and colour separation from batch to batch. In Examples:- (1 and 2) clear cellulose acetate film is coated with a solution of cyan dye and carbon tetrabromide or pentabromoethane in a mixture of equal volumes of methanol, acetone and dimethylforamide, dried, coated with ethylcellulose in toluene, dried, and then (1) coated with a solution of cyan dye and carbon tetrabromide in toluene, dried, and a solution of yellow dye and carbon tetrabromide in a mixture of methanol, acetone and dimethylformamide applied to the reverse side or (2) coated with a solution of yellow dye and pentabromoethane in toluene, dried, coated with ethylcellulose in toluene, dried and finally coated with a cold solution of magenta dye and pentabromoethane in toluene; and (3) white pigmented cellulose acetate film is successively coated, with intermediate drying, with cyan dye and carbon tetrabromide in a solvent mixture of acetone, methanol and dimethylforamide, with yellow dye, carbon tetrabromide and ethyl cellulose in toluene and with magenta dye, carbon tettrabromlde and ethyl cellulose in toluene.