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AssigneeAgfa-Gevaert
InventorsSieghart Klotzer, Erik Moisar
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A direct-positive photographic material for producing images by fogging development wherein the photographic material contains an unfogged silver halide emulsion layer. The silver halide grains in the unfogged emulsion have a layered grain structure wherein there is a first phase in which is localized a relatively high silver chloride content of at least 20 mol percent based on the total silver halide content of the grain. A second phase contains from less silver chloride than the first phase down to no silver chloride and the total silver chloride in the grain does not exceed 30 mol percent. The physical position of the first phase in the grain is not critical. The emulsion is either not chemically sensitized or only slightly sensitized. The photographic material and its use includes both producing black and white and colored photographic images and has high sensitivity to light and by fogging development yields pure image whites.
A photographic material for producing direct-positive photographic images having at least one silver halide emulsion layer having unfogged and monodispersed silver halide grains having a layered grain structure wherein 95% by weight of the silver halide grains of the emulsions have a grain diameter which does not deviate by more than 40% from the average grain diameter and which grains are not or only slightly chemically sensitized at the surface wherein the improvement comprises the unfogged silver halide grains of the emulsion have at least two phases, a localized first phase of the silver halide grains has at least 20 mol percent of silver chloride based on the total mol percent of silver halide and a second phase of the silver halide grains has less silver chloride than said first phase and said silver halide grains contain not more than 30 mol percent of silver chloride based on the silver halide of said grains based on the total mol percent of silver halide, said silver halide grains when exposed for between 1/100 to 1 second and developed for 3 minutes at 20.degree.C with an internal developer of the following description:
The process for producing direct-positive photographic images in a photographic material which comprises (a) imagewise exposing a photographic material comprised of a support and at least one light-sensitive silver halide emulsion layer which contains monodispersed, unfogged, silver halide grains with a layered grain structure wherein 95% by weight of the silver halide grains of the emulsions have a grain diameter which does not deviate by more than 40% from the average grain diameter;
Dependencies are inferred from the claim text.