[en] The present invention is an apparatus and a method for using the apparatus to maintain quality control over a radiographic imaging system by precisely exposing two areas of a film to even illumination from a light source attenuated by different precisely known amounts. Both exposures are chosen to fall on the linear portion of the film's density-log exposure curve. The film is developed and the densities of the exposed areas are sensed photometrically. The film's base plus fog density, gamma and ''processor quality factor'' (Which is a measure of the sensed film's deviation from the gamma and speed of a reference film processed in a reference processor) are automatically calculated. The processor quality factor allows faulty radiographic technique to be detected apart from faulty film or faulty processing without re-exposing the patient to additional radiation