Emulsions with tabular grain major faces formed by regions of differing iodide concentrations
AssigneeEastman Kodak Company
InventorJoe E. Maskasky
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Abstract
Radiation-sensitive emulsions are disclosed comprised of high bromide tabular grains having {111} major faces wherein a portion of the {111} major faces is formed by a central region containing at least 7 mole percent iodide and an annular band extends outwardly from the central region forming a second portion of the {111} major faces and contains less than half the iodide of the central region. The emulsions combine the advantages of both high and low surface iodide tabular grain emulsions.
Claims7
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 comprised of greater than 50 mole percent bromide, based on total silver, and having parallel {111} major faces and an average aspect ratio of at least 5, the tabular grains being comprised of regions differing in iodide concentrations,
- wherein
- one of the regions is a central region containing greater than 7 mole percent iodide, based on silver forming the central region,
- a second of the regions is an annular band containing less than half the iodide concentration of the central region, and
- the central region and the annular band each extend between and form a portion of the {111} major faces, with the central region and annular band each forming at least 5 percent of each {111} major face, and
- the emulsion contains a 4,5,6-triaminopyrimidine, a polyiodophenol or an iodo-8-hydroxyquinoline grain growth modifier.
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 comprised of greater than 70 mole percent bromide, based on total silver, and having parallel {111} major faces and an average aspect ratio of at least 5, the tabular grains comprised of regions differing in iodide concentrations,
- wherein
- one of the regions is a central region containing from greater than 7 to 30 mole percent iodide, based on silver, the central
- a second of the regions is an annular band containing less than 2 mole percent iodide, based on silver forming the annular band,
- the central region and the annular band each extend between and form a portion of the {111} major faces, with the central region forming at least 80 percent of each {111} major face and the annular band forming from 5 to 20 percent of each {111} major face, and
- the emulsion contains a 4,5,6-triaminopyrimidine, a polyiodophenol or an iodo-8-hydroxyquinoline grain growth modifier.
Dependencies are inferred from the claim text.