Abstract: A silver halide emulsion comprising radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure containing a hexacoordination complex of an iridium ion in which at least half of the coordination sites in the hexacoordination complex are provided by halogen or pseudohalogen ligands, and at least one coordination site is provided by a ligand comprising a azole ring containing a chalcogen atom and a nitrogen atom, wherein the azole ring is substituted at the 5-position with a halide ion. The invention provides emulsions containing with a preferred class of iridium dopants which are especially useful for improving reciprocity performance in silver halide emulsions with minimal or no impact on other aspects of photographic performance. These dopants give a superior balance of reciprocity and other photographic properties compared to other iridium dopants exemplified in the prior art.

Abstract: A radiation-sensitive emulsion comprised of silver halide grains (a) containing greater than 50 mole percent chloride, based on silver, (b) having greater than 50 percent of their surface area provided by {100} crystal faces, and (c) having a central portion accounting for up to 99 percent of total silver and containing a first dopant of Formula (I) and a second dopant of Formula (II): [RuL6]n  (I) wherein n is zero, −1, −2, −3 or −4, and L6 represents bridging ligands which can be independently selected, provided that at least four of the ligands are anionic ligands, and at least one of the ligands is a cyano ligand or a ligand more electronegative than a cyano ligand; [TE4(NZ)E′]r  (II) wherein T is Os or Ru; E4 represents bridging ligands which can be independently selected; E′ is E or NZ; r is zero, −1, −2 or −3; and Z is oxygen or sulfur; wherein the dopant of Formula (II) is selected from hexacoor

Abstract: A photographic silver halide emulsion is disclosed comprised of radiation sensitive composite silver halide grains including host grain portions accounting for at least 50 percent of total silver and surface portions epitaxially deposited on the host grain portions. The epitaxially deposited surface portions on the host grain portions exhibit a face centered cubic crystal lattice structure containing a hexacoordination complex of a metal from periods 4, 5 and 6 of groups 3 to 14 inclusive of the periodic table of elements in which one or more organic ligands each containing at least one carbon-to-carbon bond, at least one carbon-to-hydrogen bond or at least one carbon-to-nitrogen-to-hydrogen bond sequence occupy up to half the metal coordination sites in the coordination complex and at least half of the metal coordination sites in the coordination complex are provided by halogen or pseudohalogen ligands.

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 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 14 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: 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: Room light handleable direct reversal silver bromide emulsions, with up to 70 mole percent chloride, have a broad Dmin window when from 1.times.10.sup.-6 to 1.times.10.sup.-4 mole per silver mole of a polybromo coordination complex of iridium is incorporated in the silver halide grains. The emulsions are stabilized against deterioration on keeping with mercapto compounds.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing a carbonyl coordination ligand and a transition metal chosen from groups 8 and 9 of the periodic table of elements.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing oxo coordination ligands and a transition metal chosen from groups 6, 7, and 8 of the periodic table of elements.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains containing greater than 50 mole percent chloride and less than 5 mole percent iodide, based on total silver, with any residual halide being bromide, said grains exhibiting a face centered cubic crystal lattice structure formed in the presence of a hexacoordination complex of rhenium, ruthenium, or osmium with at least four cyanide ligands. The emulsions exhibit increased sensitivity.

Abstract: Photographic emulsions are disclosed comprised of radiation sensitive silver bromide grains optionally containing iodide. The grains exhibit a face centered cubic crystal lattice structure and are formed in the presence of a hexacoordination complex of rhenium, ruthenium, or osmium with at least four cyanide ligands.

Abstract: Photographic silver halide emulsions are disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure internally containing a nitrosyl or thionitrosyl coordination ligand and a transition metal chosen from groups 5 to 10 inclusive of the periodic table of elements.