densometer

A densometer is a scientific instrument used to measure the opacity or optical density of a translucent material. This is often a paper or film. The device works by shining a light through the material and measuring how much light passes through. A higher reading on the densometer indicates that less light has passed, meaning the material is more opaque or has a higher optical density. Conversely, a lower reading signifies greater transparency. Densometers are commonly employed in industries such as printing, papermaking, and photography. In printing, they help ensure consistent ink coverage and color reproduction. For papermakers, densometers assist in controlling the basis weight and formation of paper. Photographers use them to assess the density of negatives and prints, which directly relates to the amount of light that reached the film or paper during exposure. The measurement is typically expressed in logarithmic units of optical density. Different types of densometers exist, including transmission densometers, which measure light passing through a sample, and reflection densometers, which measure light reflected off the surface of a sample.