Abstract: The action of dibenzo-18-crown-6 as a growth modifier in the preparation of epitaxial silver halide emulsion and its complexation to silver halide crystallite were studied.Because of the complexation, the active sites (edges and corners) of the silver halide grains are partially dissolved and new crystal faces (100) come into sight, so that the crystallite could take a more stable state.Because the dibenzo-18-crown-6 can increase the solubility of silver bromide, the grain size of the emulsion prepared under its presence is larger than that prepared under normal condition.With the complexation of dibenzo-18-crown-6 to the silver bromide crystallites, several active defects were produced on their edges and corners, and when the epitaxial growth was taken place, the epitaxial components were first deposited on the active defects.

Key words: dibenzo-18-crown-6, epitaxial emulsion, modifier, complexation, defect