Abstract: A tabular grain emulsion is disclosed that combines increased speed, reduced low intensity reciprocity failure, and low levels of pressure sensitivity. The tabular grains containing greater than 70 mole percent bromide and laminae located adjacent the {111} major faces each having a thickness of less than 35 nanometers and containing at least 1 mole percent higher iodide than a host portion of the tabular grains on which they are deposited. The tabular grains contain an iridium dopant capable of reducing low intensity failure in one interior grain portion and a Group 8 speed enhancing dopant present in a concentration of from 20 to 300 molar parts per million in another interior grain portion separated from the iridium containing grain portion by at least 10 percent of the silver forming the grain structure.

Abstract: A chemically and spectrally sensitized ultrathin tabular grain emulsion is disclosed including tabular grains (a) having {111} major faces, (b) containing greater than 70 mole percent bromide and at least 0.25 mole percent iodide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, and (e) exhibiting an average thickness of less than 0.07 .mu.m.

Abstract: A chemically and spectrally sensitized tabular grain emulsion is disclosed including tabular grains (a) having major faces, (b) containing greater than 70 mole percent bromide and at least 0.25 mole percent iodide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, and (f) exhibiting an average thickness in the range of from less than 0.3 .mu.m to at least 0.07 .mu.m.

Abstract: A chemically and spectrally sensitized ultrathin tabular grain emulsion is disclosed including tabular grains (a) having {111} major faces, (b) containing greater than 70 mole percent bromide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, and (e) exhibiting an average thickness of less than 0.07 .mu.m.Improved sensitivity is observed when the surface chemical sensitization sites include silver halide protrusions of a face centered cubic crystal lattice structure forming epitaxial junctions with the tabular grains and having a higher overall solubility than at least that portion of the tabular grains forming epitaxial junctions with the protrusions and a sensitivity enhancing combination of dopants are contained in the silver halide grains including a first sensitivity enhancing dopant capable of providing shallow electron trapping sites and a second sensitivity enhancing selenium dopant.

Abstract: A chemically and spectrally sensitized ultrathin tabular grain emulsion is disclosed including tabular grains (a) having {111} major faces, (b) containing greater than 70 mole percent bromide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, and (e) exhibiting an average thickness of less than 0.07 .mu.m.It has been observed that increased speed and contrast as well as improvements in speed-granularity relationships can be realized when the surface chemical sensitization sites include epitaxially deposited silver halide protrusions forming epitaxial junctions with the tabular grains, the protrusions (a) being located on up to 50 percent of the surface area of the tabular grains, (b) having a higher overall solubility than at least that portion of the tabular grains forming epitaxial junctions with the protrusions, and (c) forming a face centered cubic crystal lattice.

Abstract: An improved spectrally sensitized ultrathin tabular grain emulsion is disclosed in which tabular grains (a) having {111} major faces, (b) containing greater than 70 mole percent bromide and at least 0.25 mole percent iodide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, (e) exhibiting an average thickness of less than 0.07 .mu.m, and (f) having latent image forming chemical sensitization sites on the surfaces of the tabular grains, are spectrally sensitized. The speed-granularity relationship of the emulsion is improved by employing in forming the surface chemical sensitization sites at least one silver salt epitaxially located on tabular grain surface sites that contain increased iodide concentrations.

Abstract: An improved spectrally sensitized ultrathin tabular grain emulsion is disclosed in which tabular grains (a) having {111} major faces, (b) containing greater than 70 mole percent bromide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, (e) exhibiting an average thickness of less than 0.07 .mu.m, and (f) having latent image forming chemical sensitization sites on the surfaces of the tabular grains, are spectrally sensitized and improved by employing in forming the surface chemical sensitization sites at least one silver salt epitaxially located on the tabular grains.

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: A photographic emulsion is disclosed in which a spectral sensitizing dye is adsorbed to the surface of octahedral silver bromide grains optionally containing iodide. The grains each contain a buried shell formed in the presence of a hexacoordination complex of iron and at least three cyanide ligands.

Abstract: A photographic emulsion is disclosed in which an infrared spectral sensitizing dye is adsorbed to the surface of silver bromide grains optionally containing iodide. The grains are formed in the presence of a hexacoordination complex of iron and at least three cyanide ligands to counteract dye desensitization.

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.

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: A photographic silver halide emulsion is disclosed comprised of radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure and internally containing rhenium ions.