An electric lamp is provided having a luminescent layer on the lamp envelope that produces visible light when impinged by ultraviolet radiation generated within the lamp. An undercoat for the electric lamp increases the luminous efficacy of the lamp. The undercoat includes a particulate non-fluorescent material derived from a sintered mixture of an aluminum oxide material with a contiguous layer of getter material which reacts with contaminants present in the lamp. The getter material is an alkaline earth metal borate material or mixtures thereof.