GB675858A - Improvements in or relating to the hardening of photographic material - Google Patents

Abstract

675,858. Hardening photographic layers. GEVAERT PHOTO-PRODUCTEN, N.V. May 5, 1950 [May 17, 1949], No. 13144/49. Class 98 (ii). 2 : 3 - Dihalogeno - dioxane or 5 : 6 - alkyl, aryl or halogen derivatives thereof such as 2 : 3 : 5 : 6 - tetrachloro - dioxane or 5 : 6- diphenyl - 2 : 3 : 5 : 6 - tetrachloro - dioxane are incorporated into a gelatin containing photographic layer such as a negative or positive gelatino-silver halide emulsion layer or an anti-halation, anti-abrasion or intermediate layer. The hardening effect may be enhanced by incorporation, also, of a carbocyclic compound having at least one nuclear hydroxyl group such as resorcinol, phloroglucinol, salicylaldehyde or resorcylaldehyde; and the use of such carbocyclic compounds together with a dioxane derivative eliminates " post-hardening ". Incorporation of the dioxane derivative may be effected by mixing it with the coating solution for the layer to be hardened or with the gelatin used for preparing this solution, by bathing the layer, after coating, in an alcohol solution of the derivative, or by provision of an adjacent gelatin layer containing the derivative. The carbocyclic compound, when used, may be incorporated similarly. In example 1, 0.2 gram of 2 : 3- dichloro-dioxane is incorporated into a kilogram of silver halide gelatin emulsion. Example 2 specifies half this quantity of dioxane derivative together with 0.5 gram resercinol and 0.05 gram resorcylaldehyde.