An improved aperture fluorescent reprographic lamp is disclosed. The lamp of the present invention includes an elongated envelope containing an ionizable medium including mercury and having electrodes at each end of the envelope: a reflector layer on a major portion of the inner surface of the envelope, a phosphor layer disposed on and coextensive with the reflector layer, and a protective coating over at least the portion of the inner surface of the lamp envelope not covered with the reflector layer. The phosphor layer comprises particles of green-emitting zinc orthosilicate phosphor which are individually coated with a non-particulate, conformal aluminum oxide coating.