| abstract |
A radiation-sensitive emulsion is disclosed comprised of cubic silver iodochlorobromide grains comprising 0.25 to about 1.5 mol % iodide, 1 to about 25 mol % chloride, and from about 73.5 to 98.75 mol % bromide, each based on total silver in the emulsion, wherein the grains have an average equivalent circular diameter of greater than 0.6 micrometers and contain from 10<-7 >to 10<-3 >mole per silver mole of a metal ion coordination complex dopant of Formula (I) in an internal region of the grains formed after 10 percent and before 95 percent of the total grain silver has been precipitated:wherein n is zero, -1, -2, -3 or -4, M is a filled frontier orbital polyvalent metal ion, other than iridium, and L6 represents bridging ligands which can be independently selected, provided that at least four of the ligands are anionic ligands, and at least one of the ligands is a cyano ligand or a ligand more electronegative than a cyano ligand. Doping of relatively large grain silver iodochlorobromide cubic grain emulsions in accordance with the invention provides optimized speed, contrast and low intensity efficiency. |