Patent ID: 6159676
Filing Date: 2000-12-12
Classification: G03C

Abstract:
An emulsion comprising non-epitaxy silver bromoiodide tabular grains of greater than or equal to about 3.7 .mu.m area weighted mean equivalent circular diameter and thiourea sensitizer having the structural formula: ##STR8## wherein each of R.sub.1, R.sub.2, R.sub.3, and R.sub.4 independently can represent an alkylene, cycloalkylene, carbocyclic arylene or heterocyclic arylene, alkarylene or aralkylene group; or taken together with the nitrogen atom to which they are attached, R.sub.1 and R.sub.2 or R.sub.3 and R.sub.4 can complete a 5- to 7-member heterocyclic ring; andeach of A.sub.1, A.sub.2, A.sub.3, and A.sub.4 independently is hydrogen or represents a carboxylic, sulfinic, sulfonic, hydroxamic, mercapto, sulfonamido or primary or secondary amino nucleophilic group;with the proviso that at least one of A.sub.1 R.sub.1 to A.sub.4 R.sub.4 contains a nucleophilic group bonded to a urea nitrogen atom through a 2- or 3-member chain and wherein said tabular grains comprise grains with a {111} major face.