DefinitionA <DENSITOMETER> is an <INSTRUMENTATION ITEM> and a <MEASURING INSTRUMENT> that measures the degree of darkness in photographic or semitransparent material. The densitometer is basically a light source aimed at a photoelectric cell which determines the density of the sample from differences in the readings
There exist 'Reflection densitometers' that measure light reflected from a surface and 'Transmission densitometers' that measure transparent materials.