Ultrafine-grain silver-halide emulsions and their properties in reflection holography

A method of preparing ultra-fine-grain silver halide emulsions is briefly described. It uses a computer controlled double-jet emulsifier to produce ultra-fine-grain emulsions. The average grain size is around 20 nm, which is measured by an automatic x-ray diffractometer and from TEM photographs. The emulsions have been used for recording reflection holograms, which are processed with an optimized solution physical developer. Reflection holograms of very low noise and diffraction efficiencies of over 40 percent are obtained in these emulsions without any pretreatment.