Densitometer

A densitometer is a device having a light-sensitive photoelectric eye to measure the degree of darkness (the optical density) of a photographic or semitransparent film or plate, or of a reflecting surface by recording photometrically its transparency (fraction of incident light transmitted). Desitometers are used for measuring color saturation by print professionals, and calibrating printing equipment. They are also used for making adjustments so outputs are consistent with the colors desired in the finished products.