Microdensitometer
A microdensitometer is a high-resolution device for determining the photographic density of a photo plate as a function of the location.
A fine beam of light shines through a photo plate . The relative movement of the plate and the light beam to one another is achieved either by moving the plate in a plane parallel to the light beam or by moving the beam itself. The light beam is weakened as it passes through the plate, depending on its degree of blackening. The proportion of light that passes through is measured.
In order to minimize the effects of the light source (lamp aging, etc.), high-quality devices use two-beam technology, in which the measuring beam is set in relation to the reference beam, which hits the sensor without being influenced .
Applies the microdensitometers among others, the digitization of astronomical photographs or fingerprints, and in the quality control of film material or textile fabric.