densitometer
/ˌdɛnsɪˈtɑmɪtər/
noun
- An instrument that measures the optical density of a material, such as photographic film or printed paper.
- The photographer used a densitometer to check the exposure of the film negatives.
- The scientist measured the darkness of the X-ray film with a densitometer.
- Print shops rely on a densitometer to ensure consistent color quality in their prints.