Abstract: A flow, or rotary type, microfilm recording apparatus for filming documents having a document transport means to move documents past an aperture area. An alternating current powered fluorescent lamp is employed for illuminating the documents in the aperture area. In order to adjust, set and maintain a substantially constant level of illumination in the aperture area and to reduce flicker, a lamp regulator circuit is provided which includes a shunted rectifier load circuit and a variable current device responsive to the illumination from the fluorescent lamp for varying the voltage drop across the shunt in accordance with the illumination.