Abstract: An improved reflector layer is provided utilizing a titanium dioxide (TiO.sub.2) admixture containing up to approximately 15 percent by weight magnesia (MgO). Said reflector layer underlies the phosphor layer, and an aluminum oxide (Al.sub.2 O.sub.3) layer can be deposited upon the phosphor layer.

Abstract: Improved magnesium aluminate gallate phosphors activated by manganese are prepared containing a minor addition of stabilizer ion to avoid brightness loss when the phosphor is heated in air. The stabilizer addition also permits major substitution of aluminum for gallium along with increased manganese activator content resulting in higher powder brightness in room temperatures, greater ultraviolet absorption, and a desirable shift in spectral peak of emission response along with better resistance to oxidation when heated in air. The phosphor is particularly useful to provide improved maintenance in low-pressure mercury lamps for reprographic applications.