Abstract: A silver halide emulsion comprising radiation sensitive silver halide grains exhibiting a face centered cubic crystal lattice structure containing a hexacoordination complex of an iridium ion in which at least half of the coordination sites in the hexacoordination complex are provided by halogen or pseudohalogen ligands, and at least one coordination site is provided by a ligand comprising a azole ring containing a chalcogen atom and a nitrogen atom, wherein the azole ring is substituted at the 5-position with a halide ion. The invention provides emulsions containing with a preferred class of iridium dopants which are especially useful for improving reciprocity performance in silver halide emulsions with minimal or no impact on other aspects of photographic performance. These dopants give a superior balance of reciprocity and other photographic properties compared to other iridium dopants exemplified in the prior art.

Abstract: An elpasolite phosphor is provided corresponding to the general formula: A2−yB1+yMe3+X6:xD wherein: A=a monovalent ion B=a monovalent ion A is different from B Me3+=a trivalent ion D is a dopant X is at least one of F, Cl, Br and I 0≦y≦1 0≦x≦0.2 and wherein said phosphor has a specific gravity (sg)≧4. An elpasolite phosphor corresponding to the general formula above is especially useful in the production of prompt emitting X-ray screens and in the production of X-ray energy storage screens.