Abstract: The present invention relates to a process of preparing radiation sensitive silver halide grains containing at least 90 mole % silver iodide and having a morphological configuration of four hexagonal bipyramids each with bases joined to form a common tetrahedron. With this process, the hexagonal bipyramid portion of the grains can be elongated and/or truncated. In addition, the fraction of silver halide grains which have a configuration of four hexagonal bipyramids is increased.

Abstract: A process is disclosed of preparing a high chloride tabular grain emulsion for photographic use. An emulsion 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, is formed in the presence of at least one 2-hydroaminoazine or xanthinoid morphological stabilizer adsorbed to surfaces of the tabular grains. Chemical sensitization of the emulsion and protonation of the morphological stabilizer are performed at least in part concurrently. Termination of protonation of the morphological stabilizer retains a portion of the morphological stabilizer on the surfaces of the chemically sensitized tabular grains.