A sensitometer which gives an intensity-scale exposure has been developed as an aid to the control of photographic processing conditions. The illumination is modulated by a photographic step tablet of 21 steps in which the exposure increases by increments of $\sqrt 2$. Positive films are exposed to an incandescent lamp operating at 2850 K, while with negative films, dyed gelatin filters are inserted in the optical system to approximate sunlight quality. A pendulum mechanism furnishes a 1/10-sec exposure time for positive and negative films. Where longer exposure times are needed, as, for example, with photographic papers, an additional manual shutter is provided. The instrument gives highly reproducible results for process control but is not calibrated in absolute units.