Tabularly banded emulsions with high bromide central grain portions
AssigneeEastman Kodak Company
InventorJoe E. Maskasky
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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.
Claims10
A radiation-sensitive emulsion comprised of a dispersing medium and silver halide grains, at least 50 percent of total grain projected area being accounted for by tabular grains of a face centered cubic crystal lattice structure having parallel {111} major faces, an average thickness of less than 0.2 .mu.m, and an average aspect ratio of at least 5, the tabular grains each being comprised of a central region and a shell differing in halide content, wherein
- the central region contains greater than 50 mole percent bromide, based on silver forming the central region,
- the shell contains at least 60 mole percent chloride, based on silver forming the shell and
- the shell is comprised of a band extending laterally outwardly from the central region and forming at least 2 percent of the {111} major faces, the band accounting for at least half the volume of the shell.
A radiation-sensitive emulsion comprised of a dispersing medium and silver halide grains, at least 70 percent of total grain projected area being accounted for by tabular grains of a face centered cubic crystal lattice structure having parallel {111} major faces, an average thickness of less than 0.2 .mu.m, a coefficient of variation of equivalent circular diameters of less than 30 percent, and an average aspect ratio of at least 5, the tabular grains each being comprised of a central region and a shell differing in halide content, wherein
- the central region contains at least 70 mole percent bromide, based on silver forming the central region,
- the shell contains at least 70 mole percent chloride, based on silver forming the shell, and
- the shell is comprised of a band extending laterally outwardly from the central region between the {111} major faces and forming at least 10 percent of the {111} major faces, the band accounting for at least 70 percent of the volume of the shell.
Dependencies are inferred from the claim text.