A darkroom exposure meter has been designed to compute from a single measurement sequence both the exposure time and the paper contrast necessary to accept the full tonal scale of the negative. The photographer moves a phototransistor probe across the projected image to sample all areas that are to show gradation in the finished print. A microcomputer accepts the digitized probe output, compares the whole range of readings with paper characteristics stored in its memory, and calculates contrast grade and exposure time. A prototype constructed on this basis has demonstrated the feasibility of this concept. Such a device can greatly improve darkroom productivity.