Light-Scattering and the Graininess of Photographic Emulsions
A. Goetz, F. W. Brown
The factors upon which the optical scattering power of a photographic emulsion depend and the relationship of the former to the graininess are investigated by a method that consists in determining the ratio of two average transparencies (T1/T2) of a moving emulsion sample of uniform density with a micro-photometric device integrating simultaneously over a large (T1) and a small (T2) section of the sample. The variation of the scattering power (defined as T1/T2) with the density is determined (a) for negative emulsions: the finer grain has the larger T1/T2; (b) for a positive emulsion directly exposed and printed through various types of negative emulsions: T1/T2 is independent of the resulting graininess; (c) for positive emulsions printed with white and ultraviolet light: T1/T2 is not affected by the wavelength of the printing light; (d) for a positive emulsion with varying gamma (0.44 to 2.5): no influence upon T1/T2 by gamma is observed.