ABSTRACT
In spite of all the advances in emulsion technology, there is still no grainless silver halide emulsion – nor, from its nature, can there ever be. All silver halide emulsions scatter light to some extent after processing, because of reflections from the grain surfaces. In black-and-white photographic negatives this doesn’t matter, and in color transparencies the scatter is reduced by the removal of the silver, leaving the image entirely in the form of transparent dye. In holographic emulsions the scattering phenomenon has a different cause, as the developed grains are mostly smaller than the wavelength of light. There are two types, Mie scattering and Rayleigh scattering. The former is independent of wavelength and occurs chiefly with larger particles, so is of little importance in holograms. The latter is inversely proportional to the fourth power of the wavelength, and causes a bluish haze that can be a nuisance in display holograms.
