Chloride containing tabular grain emulsions and processes for their preparation employing a low methionine gelatino-peptizer

A process of preparing a radiation sensitive high aspect ratio tabular grain silver chloride emulsion, wherein tabular grains of less than 0.35 .mu.m in thickness and an aspect ratio of greater than 8:1 account for greater than 50 percent of the total grain projected area, comprising

• introducing silver ion into a dispersing medium containing a gelatino-peptizer formed of less than 12 micromoles of methionine per gram,
• maintaining at least a 0.5 molar concentration of chloride ion in the dispersing medium, and
• maintaining the dispersing medium free of other halide ions.

A process of preparing a radiation sensitive high aspect ratio tabular grain silver chlorobromide emulsion optionally containing up to 1 mole percent iodide, based on silver, wherein tabular grains of less than 0.20 .mu.m in thickness aspect ratio of greater than 12:1 account for greater than 70 percent of the total grain projected area, comprising

• introducing silver ion and up to 1 mole percent iodide ion, based on silver, into a dispersing medium containing at least a 2.5.times.10.sup.-3 molar concentration of bromide ion and a gelatino-peptizer formed of less than 12 micromoles of methionine per gram and
• maintaining at least a 0.5 molar concentration of chloride ion in the dispersing medium.

A process of preparing a radiation sensitive high aspect ratio tabular grain silver bromide emulsion optionally containing up to 1 mole percent iodide, based on silver, wherein tabular grains of less than 0.20 .mu.m in thickness and an aspect ratio of greater than 12:1 account for greater than 70 percent of the total grain projected area, comprising

• providing a dispersing medium containing a gelatino-peptizer formed of less than 12 micromoles of methionine per gram, at least a 0.5 molar concentration of chloride ion, and at least a 2.5.times.10.sup.-3 molar concentration of bromide ion and
• introducing silver ion, bromide ion, and up to 1 mole percent iodide ion, based on silver, into the dispersing medium.

A radiation sensitive high aspect ratio tabular grain emulsion comprised of

• a gelatino-peptizer and
• silver halide grains which are at least 40 mole percent chloride, based on silver,
• at least 50 percent of the total projected area of said silver halide grains being accounted for by tabular grains having a thickness of less than 0.35 .mu.m and an aspect ratio of greater than 8:1.

A radiation sensitive high aspect ratio tabular grain emulsion comprised of

• a gelatino-peptizer and
• silver chloride grains,
• at least 50 percent of the total projected area of said silver chloride grains being accounted for by tabular grains having a thickness of less than 0.35 .mu.m and an aspect ratio of greater than 8:1.

A radiation sensitive high aspect ratio tabular grain emulsion comprised of

• a gelatino-peptizer and
• silver chlorobromide grains,
• at least 70 percent of the total projected area of said silver chlorobromide grains being accounted for by tabular grains having a thickness of less than 0.2 .mu.m and an aspect ratio of greater than 12:1.

A radiation sensitive high aspect ratio tabular grain emulsion comprised of

• a gelatino-peptizer and
• silver chlorobromoiodide grains,
• at least 70 percent of the total projected area of said silver chlorobromoiodide grains being accounted for by tabular grains having a thickness of less than 0.2 .mu.m and an aspect ratio of greater than 12:1.