This article or the following section is not adequately provided with supporting documents ( e.g. individual evidence ). Information without sufficient evidence could be removed soon. Please help Wikipedia by researching the information and including good evidence.
In photographic films, diffusion halo is understood to be a defect that occurs when a light beam penetrates the emulsion, is exposed and is reflected again on the emulsion particles of the film. A mostly undesirable halo arises around the actual blackening.
Today's films are usually so fine-grained that this effect does not appear or appears only very little.