Abstract: A radiation-sensitive emulsion comprised of silver halide grains including tabular grains (a) having {100} major faces, (b) containing greater than 50 mole percent chloride, based on silver, (c) accounting for greater than 30 percent of total grain projected area, (d) exhibiting an average thickness of less than 0.3 .mu.m, and (e) exhibiting an average aspect ratio of greater than 5, and a dispersing medium including a peptizer adsorbed to the silver halide grains, wherein the peptizer is a water dispersible oxidized cationic starch.

Abstract: An improved spectrally sensitized ultrathin tabular grain emulsion is disclosed in which tabular grains (a) having {111} major faces, (b) containing greater than 50 mole percent bromide, based on silver, (c) accounting for greater than 70 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, show an enhanced capability for chemical sensitization by reason of employing a cationic starch as a peptizer.

Abstract: Photographic emulsions are disclosed in which at least 50 percent of total grain projected area is accounted for by high (>90%) chloride thin (<0.2 .mu.m) high average aspect ratio (>8) tabular grains having {100} major faces each having at least one edge face oriented in an atomic plane differing from that of major faces to improve photographic performance.

Abstract: Radiation-sensitive emulsions are disclosed in which tabular grains of a face centered cubic crystal lattice structure having parallel {111} major faces and an average aspect ratio of at least 5 are comprised of a central region containing greater than 50 mole percent bromide and a tabular band containing at least 60 mole percent chloride and extending laterally outwardly from the central region to form at least 2 percent of the {111} major faces.

Abstract: Radiation-sensitive emulsions are disclosed in which tabular grains of a face centered cubic crystal lattice structure having parallel {111} major faces and an average aspect ratio of at least 5 are comprised of a central region containing greater than 50 mole percent chloride and a tabular band containing less than 40 mole percent chloride and extending laterally outwardly from the central region to form at least 25 percent of the {111} major faces.

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 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 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 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 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: Disclosed are photographic elements comprising a silver halide emulsion having incorporated therein silver halide grains, wherein the grains are essentially tabular in morphology and have at least two parallel {100} major faces and substantially equivalent {111} corner faces or substantially equivalent {110} corner faces or substantially equivalent {110} side faces.

Abstract: A radiation sensitive emulsion is disclosed containing a silver halide grain population comprised of at least 50 mole percent chloride, based on silver, in which greater than 50 percent of the total grain projected area is accounted for by ultrathin tabular grains containing a 7-azaindole type compound.

Abstract: Disclosed are photographic elements comprising a silver halide emulsion having incorporated therein a hollow silver halide grain, wherein the hollow silver halide grain internally contains at least two distinct voids. Also disclosed is a process for making photographic emulsions containing grains that internally contain at least two distinct voids.

Abstract: A photographic silver halide emulsion comprised of silver halide grains containing chloride, bromide and iodide ions in which the molar ratio of bromide ions to chloride ions ranges from 9:1 to 1:1 and the proportion of iodide has been increased.

Abstract: A process is disclosed of preparing an emulsion for photographic use comprised of silver halide grains and a gelatino-peptizer dispersing medium in which morphologically unstable tabular grains having {111} major faces account for greater than 50 percent of total grain projected area and contain at least 50 mole percent chloride, based on silver. The emulsion additionally contains at least one 2-hydroaminoazine adsorbed to and morphologically stabilizing the tabular grains. Protonation releases 2-hydroaminoazine from the tabular grain surfaces into the dispersing medium. Released 2-hydroaminoazine is replaced on the tabular grain surfaces by adsorption of a photographically useful benzimidazolium dye, thereby concurrently morphologically stabilizing the tabular grains and enhancing their photographic utility, and the released 2-hydroaminoazine is removed from the dispersing medium.

Abstract: A process is disclosed of preparing an emulsion for photographic use comprised of silver halide grains and a gelatino-peptizer dispersing medium in which morphologically unstable tabular grains having {111} major faces account for greater than 50 percent of total grain projected area and contain at least 50 mole percent chloride, based on silver. The emulsion additionally contains at least one 2-hydroaminoazine adsorbed to and morphologically stabilizing the tabular grains. Protonation releases 2-hydroaminoazine from the tabular grain surfaces into the dispersing medium. Released 2-hydroaminoazine is replaced on the tabular grain surfaces by adsorption of a photographically useful 5-iodobenzoxazolium compound, thereby concurrently morphologically stabilizing the tabular grains and enhancing their photographic utility, and the released 2-hydroaminoazine is removed from the dispersing medium.

Abstract: A radiation sensitive emulsion is disclosed containing a silver halide grain population internally free of iodide at the site of grain nucleation comprised of at least 50 mole percent chloride, based on total silver forming the grain population, in which greater than 30 percent of the grain population projected area is accounted for by tabular grains having a mean thickness of less than 0.3 .mu.m. The tabular grains combine high tabularities and relatively high aspect ratios with exceptional stability imparted by parallel major faces lying in {100} crystallographic planes.

Abstract: A photographic silver halide emulsion comprised of a high chloride silver iodohalide grain structure in which the proportion of iodide has been increased.

Abstract: Silver halide emulsions can be prepared by precipitating the silver halide grains in the presence of a peptizer comprising a water-soluble starch, said peptizer exhibiting an absorbance of less than 1.0 in the wavelength region 200 to 400 nm when measured at a concentration of 2 g/L through a 1 cm transmission path. A useful water-soluble starch having this property is potato starch. Silver halide elements sensitive in the short ultraviolet spectral region can be prepared with these emulsions.