Ultrathin tabular grain emulsion

A radiation-sensitive emulsion comprised of a dispersing medium and silver iodobromide grains, greater than 97 percent of total grain projected area being accounted for by tabular grains having {111} major faces, exhibiting an average aspect ratio of greater than 8, and containing from 1 to 10 mole percent iodide, based on total silver,

• wherein said tabular grains have a mean thickness of less than 0.07 .mu.m,
• are capable of producing, when exposed to 325 nm electromagnetic radiation at 6.degree. K., a stimulated fluorescent emission at 600 nm that is at least 5 percent of the maximum intensity of the stimulated fluorescent emission in the wavelength range of from 490 to 560 nm, and
• are comprised of tabular grains each having a central region accounting for at least 15 mole percent of total silver forming the tabular grain, an annular region laterally surrounding the central region and accounting for up to 10 mole percent of total silver forming the tabular grain, and a peripheral region laterally surrounding the annular region and accounting for greater than 25 percent of total silver forming the tabular grain,
• said annular region exhibiting an iodide concentration exceeding that of said central and peripheral regions by at least 1 mole percent.