film speed(redirected from ISO (photography))
Also found in: Dictionary.
the relative sensitivity of film emulsion to light or radiation exposure; speed is inversely related to detail resolution.
The sensitivity of a photographic medium (e.g., a radiograph) to light or radiation. The film speed is determined by: the size of its silver halide crystals; the thickness of the emulsion; and the presence of radiosensitive dyes. Films are described as “fast” if the film requires little radiation to produce an image and “slow” if more radiation is needed.
film speed(film spēd)
Relative sensitivity of film emulsion to light or radiation exposure; is inversely related to detail resolution.