A Sr(Al,Mg).sub.12O.sub.19:Ce,Pr phosphor is described wherein the phosphor has an increased sensitivity to excitation by 185 nm radiation compared to a Sr(Al,Mg).sub.12O.sub.19:Ce phosphor. The Ce,Pr-coativated strontium magnesium aluminate phosphor emits ultraviolet (UV) radiation at about 306 nm in the UVB region. Suntan lamps made with this phosphor exhibit improved performance over lamps made with a commercial Sr(Al,Mg).sub.12O.sub.19:Ce phosphor.