Abstract: A process is disclosed of preparing a radiation sensitive silver halide emulsion comprising reacting silver and halide ions in a dispersing medium in the presence of a metal hexacoordination or tetracoordination complex having at least one organic ligand containing a least one carbon-to-carbon bond, at least one carbon-to-hydrogen bond, or at least one carbon-to-nitrogen-to-hydrogen bond sequence and at least half of the metal coordination sites occupied by halide or pseudohalide ligands. The metal forming the complex is chosen from periods 4, 5 and 6 and groups 3 to 13 inclusive of the periodic table of elements. The incorporation of the transition metal ion dopant and at least one organic ligand into the cubic crystal lattice of the silver halide grains can be used to improve photographic performance.

Abstract: The present invention provides a photographic silver halide emulsion containing at least two grain surface modifiers. The grain surface modifiers comprise a transition metal complex containing a transition metal chosen from Groups V to X, inclusive, of the periodic table and a nitrosyl or thionitrosyl ligand; and a transition metal selected from Group VIII of the periodic table.

Abstract: The present invention provides a photographic emulsion comprising silver halide grains, a dopant, and a grain surface modifier. The dopant is a transition metal selected from Group VIII of the periodic table. The grain surface modifier is characterized in that it comprises a transition metal complex having nitrosyl or thionitrosyl ligands with a transition metal selected from Groups V to X of the periodic table.

Abstract: Photographic emulsions are disclosed comprised of radiation sensitive silver iodobromide grains, at least 50 percent of the total projected area of said silver iodobromide grains being accounted for by tabular grains exhibiting a mean tabularity of greater than 5, at least 10 percent of which are comprised of two opposed parallel major crystal faces, a host stratum having an iodide content of at least 4 mole percent, and laminar strata containing less than 2 mole percent iodide interposed between said host stratum and said opposed major crystal faces.The emulsions are characterized in that each of the laminar strata is comprised of a surface layer forming one of the major surfaces and having a thickness in the range of from 20 to 350 .ANG. and a subsurface layer located immediately beneath and in contact with the surface layer containing a hexacoordination complex of a Group VIII period 4 or 5 metal and at least three cyanide ligands.