Silver chloride emulsions of modified crystal habit and processes for their preparation

In a double-jet precipitation process of preparing a radiation-sensitive photographic emulsion comprised of a dispersing medium and tabular silver halide grains, the halide content of which is at least 75 mole percent chloride and up to 6 mole percent iodide, based on silver, any remaining halide being bromide,

• the improvement comprising concurrently introducing aqueous silver and chloride salt solutions into a reaction vessel containing at least a portion of the dispersing medium in the presence of a crystal habit modifying amount of an aminoazaindene and a peptizer having a thioether linkage to precipitate tabular grains accounting for at least 50 percent of the total projected area of the total grain population precipitated.

A radiation-sensitive photographic emulsion comprising a dispersing medium and silver halide grains which are at least 75 mole percent chloride and up to 6 mole percent iodide, based on silver, any remaining halide being bromide,

• at least 70 percent of the total projected area of said silver halide grains being provided by tabular grains having a thickness less than 0.5 micron, a diameter of at least 0.6 micron, and an average aspect ratio greater than 12:1,
• said tabular grains having two opposed substantially parallel major crystal faces lying in {111} crystal planes and at least one peripheral edge lying parallel to a <211>
• crystallographic vector lying in the plane of one of said major faces.

A radiation-sensitive photographic emulsion comprising a dispersing medium and silver halide grains which are at least 75 mole percent chloride and up to 6 mole percent iodide, based on total halide, any remaining halide being bromide,

• at least 70 percent of the total projected area of said silver halide grains being provided by tabular grains having a thickness of less than 0.5 micron, a diameter of at least 0.6 micron, and an average aspect ratio of at least 12:1,
• said tabular grains having two opposed substantially parallel major crystal faces lying in {111} crystal planes, and
• said tabular grains containing bromide in a central grain region, said bromide accounting for at least 1 mole percent of the total halide present in said tabular grains.