GB1257257A - - Google Patents

Abstract

1,257,257. Photographic silver halide material EASTMAN KODAK CO. April 17, 1969 April 18, 1968], No. 19616/69. Heading G2C. A photographic element comprises a support, and (a) unfogged, surface latent image, iodidecontaining silver halide grains and (b) fogged, internal latent image silver halide grains, said grains being in the same layer on the support or in adjacent layers, which are contiguous or separated by an intermediate layer, said element also comprising above or below said layer or adjacent layers, another layer, (1), comprising unfogged silver halide grains in which said halide comprises less than 10 mole per cent iodide, if any, and which have a photographic surface sensitivity which is less than<SP> 1</SP>/ 10 th that of said surface latent image, iodide-containing silver halide grains(a). Grains (a) and some of grains (b) may be in one layer and the remainder of the (b) grains are in an adjacent layer as defined above. Layer (1) may be next to the support, the layer of grains (b) being directly over layer (1) and the layer of grains (a) being over the layer of grains (b). The unfogged, surface latent image, iodide-containing silver halide grains (a) preferably contain from 0À5 to 10 mole per cent iodide. The unfogged iodide-containing grains (a) are preferably chemically and spectrally sensitized. The unfogged, iodide-containing silver halide grains (a) are preferably silver bromoiodide, and the molar ratio of said grains (a) to said grains (b) is preferably at least 1:1. The halide is said silver halide grains in layer (1) contains 30 to 65 mole per cent chloride, the remainder being silver bromide. The molar ratio of said grains (a) to the silver halide grains in layer (1) is preferably from 20:1 to 1:1. The layer (1) of the present invention reduces fog and speed loss upon development of the combination of various surface latent image grains with various internally fogged latent image grains, especially when continuous processing tanks or developer baths are used where developers are not replenished or changed for long periods of time.