Emulsions and photographic elements containing silver halide grains having icositetrahedral crystal faces

Claim 2

A silver halide photographic emulsion comprised of radiation sensitive silver halide grains of a cubic crystal lattice structure comprised of icositetrahedral crystal faces.

Claim 3

A silver halide photographic emulsion according to claim 1 wherein said silver halide grains comprised of icositetrahedral crystal faces are silver bromide grains.

Claim 4

A silver halide photographic emulsion according to claim 1 wherein said silver halide grains comprised of icositetrahedral crystal faces are silver chloride grains.

Claim 5

A silver halide photographic emulsion according to claim 1 wherein said silver halide grains comprised of icositetrahedral crystal faces contain at least one of bromide and chloride ions and optionally contain a minor proportion of iodide ions based on total silver.

Claim 6

A silver halide photographic emulsion according to claim 1 wherein said silver halide grains are additionally comprised of at least one of cubic and octahedral crystal faces.

Claim 7

A silver halide photographic emulsion according to claim 1 wherein said silver halide grains are regular icositetrahedral grains.

Claim 8

A silver halide photographic emulsion according to claim 1 wherein a grain growth modifier is adsorbed to said icositetrahedral crystal faces.

Claim 9

A silver halide photographic emulsion according to claim 1 wherein said icositetrahedral crystal faces satisfy the Miller index assignment {hll}, wherein h and l are integers greater than zero, h is greater than l, and h is no greater than 5.

Claim 10

A silver halide photographic emulsion according to claim 8 wherein said icositetrahedral crystal faces exhibit a {211}, {311}, {322}, {522}, or {533} Miller index.

Claim 11

A silver halide photographic emulsion according to claim 9 wherein a grain growth modifier is present in said emulsion chosen from the class consisting of a 4-hydroxy-6-methyl-1,3,3a,7-tetraazaindene, sodium salt; 2-mercaptoimidazole; 4-hydroxy-6-methyl-2-methylmercapto-1,3,3a,7-tetraazaindene; 7-ethoxycarbonyl-6-methyl-2-methylthio-4-oxo-1,3,3a,7-tetraazaindene; 2-methyl-5-nitro-1-H-benzimidazole; 3-ethyl-5-(3-ethyl-2-benzothiazolinylidene)rhodanine; 5-(1,3-dithiolan-2-ylidene)-3-ethylrhodanine; 5-(3-ethyl-2-benzothiazolinylidene)-3-β-sulfoethylrhodanine; 5-anilinomethylene-3-(2-sulfoethyl)rhodanine; 3-(1-carboxyethyl)-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]rhodanine; 3-(3-carboxypropyl)-5-[(3-ethyl-2-benzoxazolinylidene)ethylidene]rhodanine; 3-(2-carboxyethyl)-5-(1-ethyl-4-pyridinylidene)rhodanine; 3-carboxymethyl-5-(2-pyrrolino-1-cyclopenten-1-ylmethylene)rhodanine, sodium salt; 3-ethyl-5-(3-methyl-2-thiazolidinylidene)rhodanine; 3-carboxymethyl-5-(2,6-dimethyl-4(H)-pyran-4-ylidene)rhodanine; 5-(5-methyl-3-propyl-2-thiazolinylidene)-3-propylrhodanine, and 3-ethyl-5-[3-(3-sulfopropyl)2-benzothiazolinylidene]-rhodanine, triethylamine salt.

Claim 12

A photographic element containing an emulsion according to claim 1.