Abstract: Rare earth oxysulfide phosphors and processes for creating the phosphors are disclosed.One process involves wet milling a material comprising a rare earth oxysulfide, removing soluble impurities, drying, forming a relatively uniform admixture comprising the dried material and aluminum oxide with the aluminum oxide content being from about 0.1 to about 1.0 weight percent of the admixture, followed by heating the admixture at a sufficient temperature for a sufficient time to form the phosphor.Another process involves the wet milling, soluble impurity removal and drying steps described above. The dried material is then dry milled without aluminum oxide, and heated as described above.Another process involves the wet milling, soluble impurity removal, drying, dry milling, and heating steps described above except that the material is dry milled with from about 0.1 to about 1.0 weight percent of aluminum oxide.