Sensitometry
Sensitometry is the science of measuring the response of photographic materials.
The response of film to light is one in which light energy causes a darkening in the emulsion.
This generally takes place in two stages:
- Exposure to light, [where the darkening that occurs is normally of such microscopic proportions as to be invisible to the naked eye. This image is then said to be a latent image]
- Development in which the exposed emulsion is immersed in a chemical solution capable of amplifying the latent image while leaving the unexposed crystals in the emulsion unaffected.
To measure the effect light has on film as seen on the processed film it is necessary to be able to measure both the amount of light [called the Exposure] and the degree of darkening of the film [called Density].
