Describes the phenomenon where if the same total exposureThe amount of light that reaches the film (or camera sensor). It determines how light or dark an image is. The exposure of an image is determined by the aperture, shutter speed, and film speed (ISO). During exposure, the sensors or chemicals on the film in analogue models, are subjected to the light outside the camera for a certain time. is given to photographic material over a longer period of time, then the density of the image generated is lower (effective speed is reduced). It is caused by a reduced efficiency in forming stable development centres with lower levels of light.
