Resolution Sensitivity

(Russian, informatsionnaia chuvstvitel’nost’), a characteristic of photosensitive emulsion layers that describes their capacity to record an individual optical signal or unit of optical information and to make it discernible from adjacent recorded signals.

In ordinary silver halide photographic materials, high photographic contrast and photographic sensitivity are factors that contribute to a high resolution sensitivity; graininess and light scattering by the emulsion are factors that reduce resolution sensitivity. Thus, the index of resolution sensitivity for such films is taken as the ratio GS/σ_D ω where G is the increase along the ordinate of the characteristic curve per unit of length along the abscissa in the linear segment of the characteristic curve, S is the photographic sensitivity value, σ_D is the mean square granularity (the mean square value of the variations in optical density D of a macroscopically uniform section of photographic blackening; the variations are caused by the grain structure in the section), and ω is the area of the scattering section in the image of a luminous point on the photosensitive layer. (SeeSENSITOMETRY for a discussion of the quantities G and S.)