Densitometer

A densitometer is a scientific instrument used to measure the density of a material, which is how much mass exists in a given volume. In practical terms, it often measures how much light can pass through a film or photographic print. This is important in photography and printing, as it helps ensure images have the right contrast and quality. Densitometers can also be used in various fields, including materials science and quality control, to assess thickness or concentration of substances. Essentially, they help evaluate how opaque or transparent a material is.