Silver salt direct positive emulsion

Abstract

.Iadd.Light-sensitive photographic direct positive silver salt emulsions for use in photographic elements are disclosed. The emulsions contain silver salt grains, typically silver halide grains. The silver salt grains are comprised of a core containing centers which promote the deposition of photolytic silver and a shell covering the core. The shell is fogged and develops to silver without exposure. .Iaddend.

I claim: .[.1. A light-sensitive photographic direct positive emulsion containing grains comprising a central core of a water-insoluble silver salt containing centers which promote the deposition of photolytic silver and an outer shell covering said core comprising a fogged water-insoluble silver salt that develops to silver without exposure..]. .[.2. The process which comprises exposing to an image an emulsion as described in claim 1 and thereafter developing the exposed emulsion in a surface image silver halide developing composition of low silver halide solvent action sufficient to develop unexposed grains of the emulsion without substantial development of the image-wise exposed grains of the emulsion..]. .[.3. A light-sensitive photographic direct positive emulsion containing grains comprising a central core of silver halide containing centers which promote the deposition of photolytic silver and an outer shell covering said core comprising a fogged silver halide that develops to silver without exposure..]. .[.4. A light-sensitive photographic direct positive emulsion containing silver halide grains comprising a central core of chemically sensitized silver halide and an outer shell covering said core comprising fogged silver halide that develops to silver without exposure..]. .[.5. The direct positive emulsion of claim 4 wherein said outer shell is fogged with a reduction sensitizer..]. .[.6. The direct positive emulsion of claim 4 wherein said outer shell is fogged with a gold salt and a reduction sensitizer..]. .[.7. A light-sensitive photographic direct positive emulsion containing grains comprising a central core of a water-insoluble silver salt containing centers which promote the deposition of photolytic silver, said centers being obtained by treatment of said core with an iridium salt, and an outer shell covering said core comprising a fogged water-insoluble silver salt that 
     
        develops to silver without exposure..]. 8. A light-sensitive photographic direct positive emulsion containing silver halide grains comprising a central core of silver halide containing centers which promote the deposition of photolytic silver, said centers being obtained by treatment of said core with an iridium salt, and an outer shell covering said core comprising fogged silver halide that develops to silver without exposure. .[.9. A light-sensitive photographic direct positive emulsion containing silver halide grains comprising a central core of fogged silver halide and an outer shell covering said core comprising fogged silver halide, said outer shell being fogged subsequent to the formation of said outer 
     
     
        shell..]. 10. A light-sensitive photographic direct positive gelatino emulsion containing silver chloride grains comprising a central core of silver chloride containing centers which promote the deposition of photolytic silver, said centers being obtained by treatment of said core with an iridium salt, and an outer shell covering said core comprising fogged silver chloride that develops to silver without exposure. .Iadd. 11. A light-sensitive photograhic direct positive emulsion containing grains comprising a central core of silver halide containing centers which are formed by treatment with a salt of a noble Group VIII metal and which promote the deposition of photolytic silver and an outer shell covering said core comprising a fogged silver halide that develops to silver without exposure. .Iaddend..Iadd. 12. The direct positive emulsion of claim 11 wherein said outer shell is fogged with a reduction sensitizer. .Iaddend. .Iadd. 13. The direct positive emulsion of claim 11 wherein the outer shell is fogged with a gold salt and a reduction sensitizer..Iaddend..Iadd. 14. A light-sensitive photographic direct positive emulsion containing grains comprising a central core of silver halide containing centers which are formed by treatment with an iridium salt and which promote the deposition of photolytic silver and an outer shell covering said core comprising a fogged silver halide that develops to silver without exposure wherein the outer shell is fogged with a gold salt and a reduction sensitizer. .Iaddend.