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 method for forming a radiation-sensitive high chloride silver halide emulsion is described comprising growing cubical silver halide grains having a central portion accounting for up to 98 percent of total silver of the grains which central portion contains an iridium coordination complex dopant, and chemically sensitizing the surface of the emulsion grains at a pH of at least 5.75. Localized addition of the known in the art reciprocity-controlling iridium dopants to an internal portion of the emulsion grains and chemical finishing of such an emulsion at elevated pH conditions improves reciprocity and latent image stability of the formed high chloride emulsions.

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 (i) a first dopant comprising an iridium coordination complex containing at least one thiazole ligand and (ii) a second dopant comprising an iridium coordination complex containing at least one substituted thiazole ligand. The combined use of first and second iridium dopants in accordance with the invention provides enhanced toe contrast softening, and can also result in improved latent image keeping stability relative to that expected from the individual effects of such dopants.

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):

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 (i) a first dopant comprising an iridium coordination complex containing at least one thiazole ligand and (ii) a second dopant comprising an iridium coordination complex containing at least one substituted thiazole ligand. The combined use of first and second iridium dopants in accordance with the invention provides enhanced toe contrast softening, and can also result in improved latent image keeping stability relative to that expected from the individual effects of such dopants.

Abstract: The invention relates to a photographic element comprising a base material, at least one exposure side photosensitive silver halide layer, and at least one backside photosensitive silver halide layer, wherein said face side photosensitive layer has lower speed than said backside photosensitive layer, and wherein said base material has a percent transmission of between 35 and 60%.

Abstract: A radiation-sensitive emulsion is disclosed comprised of cubical silver halide grains containing from 0.05 to 3 mole percent iodide, based on total silver, and an iridium coordination complex dopant, wherein (i) the iodide is incorporated in the grains in a controlled, non-uniform distribution forming a core containing at least 50 percent of total silver, an iodide free surface shell having a thickness of greater than 50 Å, and a sub-surface shell that contains a maximum iodide concentration, and (ii) the iridium coordination complex dopant is incorporated into the sub-surface shell or into a region of the core extending up to 60% of the total silver into the grain from the sub-surface shell. Speed and reciprocity of iodochloride emulsions can be improved by localized addition of known in the art reciprocity-controlling iridium dopants in relation to high iodide region of the grain.

Abstract: A radiation-sensitive emulsion is disclosed 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 from 95 to 99 percent of total silver and containing two dopants selected to satisfy each of the following class requirements: (i) a hexacoordination metal complex which satisfies the formula (I)[ML.sub.6 ].sup.nwherein n is zero, -1, -2, -3 or -4; M is a filled frontier orbital polyvalent metal ion, other than iridium; and L.sub.6 represents bridging ligands which can be independently selected, provided that 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; and (ii) an iridium coordination complex containing a thiazole or substituted thiazole ligand.

Abstract: The invention relates to a photographic emulsion comprising silver iodochloride grains, said grains further comprising iridium, said grains chemically sensitized with gold in an amount of between 120 and 200 mg gold per silver mole and sulfur in an amount between 0.1 and 20 mg sulfur per silver mole, 1-(3-acetamidophenyl)-5-mercaptotetrazole, 1-phenyl-5-mercaptotetrazole, and a disulfide compound represented by the following formula: ##STR1## wherein X is independently --O--, --NH-- or --NR--, where R is a substituent;m and r are independently 0, 1 or 2;X is --H or a cationic species;Ar is an aromatic group; andL is a linking group, where p is 0 or 1.

Abstract: A radiation-sensitive high chloride emulsion is disclosed comprised of grains predominantly bounded by {100} crystal faces and internally containing three dopants each selected to satisfy a different one of the following class requirements: (i) a metal coordination complex containing a nitrosyl or thionitrosyl ligand in combination with a transition metal chosen from groups 5 to 10 inclusive of the periodic table of elements, (ii) a shallow electron trapping dopant, and (iii) an iridium coordination complex having ligands each of which are more electropositive than a cyano ligand. A gelatino-peptizer for the grains is employed that contains less than 30 micromoles of methionine per gram. The dopants and peptizer in combination increase contrast and provide a highly unexpected increase in high density contrast.

Abstract: An electronic printing method is disclosed which comprises subjecting a radiation sensitive silver halide emulsion layer of a recording element to actinic radiation of at least 10.sup.-4 ergs/cm.sup.2 for up to 100.mu. seconds duration in a pixel-by-pixel mode. The silver halide emulsion layer is comprised of grains predominantly bounded by {100} crystal faces and internally containing three dopants each selected to satisfy a different one of the following class requirements: (i) a metal coordination complex containing a nitrosyl or thionitrosyl ligand in combination with a transition metal chosen from groups 5 to 10 inclusive of the periodic table of elements, (ii) a shallow electron trapping dopant, and (iii) a iridium coordination complex having ligands each of which are more electropositive than a cyano ligand. A gelatino-peptizer for the grains is employed that contains less than 30 micromoles of methionine per gram.

Abstract: The present invention provides a photographic emulsion comprising a silver halide grains containing at least two dopants. The dopants comprise an osmium-based transition metal complex containing a nitrosyl or thionitrosyl ligand, and a transition metal complex containing a transition metal selected from Group 8 of the periodic table.

Abstract: The invention provides a cyan color producing silver halide emulsion layer or a magenta color producing silver halide emulsion layer wherein said at least one layer has an exposure range of at least 0.6 log E from the point where the instantaneous contrast is 1.0 and wherein the instantaneous contrast of said layer increases as a function of increasing exposure over at least 70 percent of said exposure range.

Abstract: The present invention provides a photographic emulsion comprising comprising silver halide grains, an iridium containing hexacoordination complex, and at least two grain surface modifiers, wherein the first of the grain surface modifiers is a transition metal complex comprising a nitrosyl or thionitrosyl ligand with a transition metal selected from the Groups 5 to 10, inclusive, of the periodic table, and the second of the grain surface modifiers is a transition metal complex comprising a transition metal, other than iridium, which is selected from Groups 7 to 10, inclusive, of the periodic table.

Abstract: The present invention provides a photographic emulsion silver halide grains having incorporated therein or thereon a dopant, a grain surface modifier, and a hexacoordination complex comprising iridium, wherein the dopant is a transition metal complex comprising a nitrosyl or thionitrosyl ligand with a transition metal selected from the Groups 5 to 10 of the periodic table, and the grain surface modifier is a transition metal complex comprising a transition metal, other than iridium, which is selected from Groups 7 to 10 of the periodic table.

Abstract: The present invention provides a photographic emulsion silver halide grains having incorporated therein or thereon a dopant, a grain surface modifier, and a hexacoordination complex comprising iridium, wherein the grain surface modifier is a transition metal complex comprising a nitrosyl or thionitrosyl ligand with a transition metal selected from the Groups 5 to 10, inclusive, of the periodic table, and the dopant is a transition metal complex comprising a transition metal, other than iridium, which is selected from Groups 7 to 10 of the periodic table.

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: The invention provides a cyan color producing silver halide emulsion layer or a magenta color producing silver halide emulsion layer wherein said at least one layer has an exposure range of at least 0.6 log E from the point where the instantaneous contrast is 1.0 and wherein the instantaneous contrast of said layer increases as a function of increasing exposure over at least 70 percent of said exposure range.

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 complex comprising a nitrosyl or thionitrosyl ligand with a transition metal selected from the group consisting of ruthenium and osmium. The grain surface modifier is a transition metal selected from Group VIII of the periodic table.