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: Radiation-sensitive emulsions are disclosed comprised of high bromide tabular grains having {111} major faces wherein a portion of the {111} major faces is formed by a central region containing at least 7 mole percent iodide and an annular band extends outwardly from the central region forming a second portion of the {111} major faces and contains less than half the iodide of the central region. The emulsions combine the advantages of both high and low surface iodide tabular grain emulsions.

Abstract: A film is disclosed for duplicating a silver image in a radiographic film. A single monodispersed fogged direct-positive emulsion layer is employed. To extend exposure latitude the emulsion layer contains micro-crystalline particles of a dye that competes with the fogged direct positive grains of the emulsion layer for absorption of exposing radiation and can be decolorized during photographic processing.

Abstract: Tabular grain emulsions of enhanced photographic sensitivity are disclosed in which the tabular grains contain a maximum surface iodide concentration along their edges and a lower surface iodide concentration within their corners than elsewhere along their edges.

Abstract: A radiation-sensitive emulsion is disclosed in which greater than 90 percent of total grain projected area is accounted for by high aspect ratio tabular grains, the halide content of which is primarily bromide, but with a speed enhancing amount of iodide also present. The tabular grains are ultrathin and exhibit low temperature stimulated fluorescence indicative of the iodide crystal lattice modifications produced by abrupt iodide introduction known to enhance photographic speed. Tabular grain structures are present having a central region accounting for at least 5 mole percent of total silver forming the tabular grain, an annular region laterally surrounding said central region and exhibiting a maximum iodide concentration, and a peripheral region laterally surrounding the annular region and accounting for greater than 25 percent of total silver forming the tabular grain.

Abstract: A process is disclosed for the precipitation of a silver halide emulsion containing host grains having {100} crystal faces that are sensitized by the deposition of protrusions at the intersections of the {100} crystal faces. Protrusion growth is achieved by undertaking final silver introduction in the presence of a benzothiazolium site director containing a 5-position electron withdrawing ring substituent adsorbed to the {100} crystal faces of the grains being grown.

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: Tabular grain emulsions are disclosed in which the tabular grains have average thicknesses of less than 0.07 .mu.m and average equivalent circular diameters of at least 0.7 .mu.m. These ultrathin tabular grain emulsions are improved by the incorporation of at least 0.4 mole percent chloride along with >50 mole percent bromide and, optionally, iodide. Greater than 97 percent of total grain projected area can be accounted for by the tabular grains. The emulsions exhibit reduced pressure sensitivity, exhibit increased developability and exhibit reduced native sensitivity to the blue region of the spectrum.

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: An electronic printing method 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 microseconds duration in a pixel-by-pixel mode is disclosed. The radiation sensitive silver halide emulsion layer contains a silver halide grain population comprising at least 50 mole percent chloride, based on silver, forming the grain population projected area. At least 50 percent of the grain population projected area is accounted for by tabular grains that are bounded by {100} major faces having adjacent edge ratios of less than 10, each having an aspect ratio of at least 2.

Abstract: The invention concerns a process for obtaining emulsions of the core/shell type having a low fog level.The process consists of precipitating, by the double jet method, a photographic emulsion comprising core-shell silver halide grains, the concentrations of halides varying progressively during at least the formation of the core.Application to reversal or negative photographic products is disclosed.

Abstract: A photographic element is disclosed comprised of a support and a sequence of superimposed blue, green and red recording silver halide emulsion layer units that produce images of the same hue upon imagewise exposure and photographic development. A first interlayer unit overlies the emulsion layer unit nearest the support and is capable of transmitting to it imagewise exposing radiation this emulsion layer unit is intended to record. A second interlayer unit underlies the emulsion layer unit farthest from the support and is capable of transmitting to the emulsion layer units lying nearer the support imagewise exposing radiation these emulsion layer units are intended to record. The imagewise exposed photographic element is photographically developed and fixed to produce a silver image in each of the emulsion layer units.

Abstract: A grain growth process is disclosed for providing an ultrathin tabular grain emulsion in which the average equivalent circular diameter of tabular grains is increased. An aqueous dispersion is provided containing high bromide grains having an average thickness of less or equal to that of the ultrathin tabular grains to be produced, the dispersion having a pH in the range of from 2 to 8 and a limited stoichiometric excess of bromide ions. An 8-hydroxyquinoline that contains at least one iodo substituent is introduced into the dispersing medium as a grain growth modifier. The aqueous dispersion containing the iodo-8-hydroxyquinoline grain growth modifier is held at 40.degree. C. or a convenient higher temperature until greater than 50 percent of total grain projected area is accounted for by ultrathin tabular grains having {111} major faces of a higher average equivalent circular diameter than the starting grains and an average aspect ratio of at least 5.

Abstract: A photographic element is disclosed comprised of a sequence of superimposed blue, green and red recording silver halide emulsion layer units at least two of which produce images of the same hue upon processing. The photographic element is additionally comprised of, interposed between the two emulsion layer units, an interlayer unit for transmitting to the emulsion layer unit of the two units which is nearer the support, electromagnetic radiation that this emulsion layer unit is intended to record and capable, after processing, of reflecting electromagnetic radiation within at least one wavelength region.

Abstract: An improved preparation of high chloride {100} tabular grain emulsions that relies on iodide ions to produce tabular grain growth is disclosed. By delaying iodide ion introduction until after the initiation of grain nucleation the proportion of total grain projected area accounted for by high chloride {100} tabular grains is increased. The projected areas of the {100} tabular grains can exceed 95 percent of total grain projected area.

Abstract: A grain growth process is disclosed for providing an ultrathin tabular grain emulsion in which the average equivalent circular diameter of tabular grains is increased. An aqueous dispersion is provided containing high bromide starting grains having an average thickness of less or equal to that of the ultrathin tabular grains to be produced, the dispersion having a pH in the range of from 1.5 to 8 and a limited stoichiometric excess of bromide ions. A phenol that is incapable of reducing the starting grains and that contains at least two iodo substituents is introduced into the dispersing medium as a grain growth modifier. The aqueous dispersion containing the phenol grain growth modifier is held at 40.degree. C. or a convenient higher temperature until greater than 50 percent of total grain projected area is accounted for by ultrathin tabular grains having {111} major faces of a higher average equivalent circular diameter than the starting grains and an average aspect ratio of at least 5.

Abstract: A process is disclosed of preparing a high chloride {111} tabular grain emulsion. Tabular grains are formed having {111} major faces, containing at least 50 mole percent chloride and less than 5 mole percent iodide, based on silver, and accounting for at least 50 percent of total grain projected area by introducing silver ion into a gelatino-peptizer dispersing medium containing a stoichiometric excess of chloride ions with respect to silver ions and a phenol that is incapable of reducing silver chloride and has at least two iodo substituents, which acts as a grain growth modifier.

Abstract: A grain growth process is disclosed for providing an ultrathin tabular grain emulsion in which the equivalent circular diameter of tabular grains is increased. An aqueous dispersion is provided containing high bromide seed grains having an average thickness of less or equal to that of the ultrathin tabular grains to be produced, the dispersion having a pH in the range of from 4.6 to 9.0 and a limited stoichiometric excess of bromide ions. An aminopyrimidine grain growth modifier containing mutually independent amino substituents, the 4 and 6 ring position substituents being hydroamino substituents, is introduced into the dispersing medium. The aqueous dispersion containing the aminopyrimidine grain growth modifier is held at room temperature or a convenient higher temperature until greater than 50 percent of total grain projected area is accounted for by ultrathin tabular grains having {111} major faces of a higher average equivalent circular diameter than the seed grains.

Abstract: A process is disclosed of preparing a high chloride {111} tabular grain emulsion. Tabular grains are formed having {111} major faces, containing at least 50 mole percent chloride and less than 5 mole percent iodide, based on silver, and accounting for at least 50 percent of total grain projected area by introducing silver ion into a gelatino-peptizer dispersing medium containing a stoichiometric excess of chloride ions with respect to silver ions and an iodo-substituted 8-hydroxyquinoline, which acts as a grain growth modifier.

Abstract: A radiation sensitive emulsion is disclosed that improves the light absorption of high chloride tabular grain emulsions in the longer wavelength half of the blue spectrum. The tabular grains each have a tabular substrate portion containing at least 50 mole percent chloride, based on silver, bounded by {100} major faces and a portion deposited on the substrate containing a silver salt exhibiting a higher solubility than silver iodide and a higher absorption of blue light at wavelengths longer than 450 nm than silver iodide.