ABSTRACT
Sensitometry in silver-based photography which is the subject of this chapter is assessed by the amount of blackening, silver image formation, which takes place. It is possible to produce photographs without any knowledge of sensitometry, but to obtain the best performance from photographic systems an understanding of the principles governing the response of imaging systems is invaluable. As sensitometry is concerned with the measurement of the performance of photographic materials and other lightsensitive systems, it is necessary to use precise terminology in defining the quantities that are measured. When a photograph is taken, light from the various areas of the subject falls on corresponding areas of the film. When light passes through a photographic image it is partially scattered. Colour photographic images, however, are essentially non-scattering, so that they possess Callier coefficients close to unity. Photographic materials differ both in the maximum slope that can be achieved and in the rate at which the value of the slope increases.
