Abstract: A radiation-sensitive spectrally sensitized tabular grain emulsion is disclosed which exhibits improved speed and contrast. The tabular grains have {111} major faces, contain greater than 70 mole percent bromide and up to 10 mole percent iodide, based on silver, account for greater than 90 percent of total grain projected area, and have an average equivalent circular diameter of at least 3.5 .mu.m. The tabular grains have latent image forming chemical sensitization sites on their surfaces including epitaxially deposited silver halide protrusions of a face centered cubic rock salt crystal lattice structure forming epitaxial junctions with the tabular grains.

Abstract: A supersensitizing dye combination for silver halide photographic materials is disclosed. The combination is of a first dye according to the formula: ##STR1## Z.sub.1 and Z.sub.2 each independently represents the atoms necessary to complete a substituted or unsubstituted heterocyclic nucleus,each L independently represents a substituted or unsubstituted methine group,n is a positive integer of from 1 to 4,p and q each independently represents 0 or 1,X represents a cation as needed to balance the charge of the molecule,A and A' each independently represents a divalent linking group such that at least one of H--A--SO.sub.3 H and H--A'--SO.sub.3 H would each have a log P value that is more negative than -0.3, anda second dye, having an oxidation potential that is at least about 0.08 volts less positive than the oxidation potential of the first dye and a reduction potential that is equal to or more negative than the reduction potential of the first dye, according to the formula: ##STR2## Z.sub.3 and Z.sub.