PROCESS OF PREPARING A TABULAR GRAIN SILVER BROMOIODIDE EMULSION AND EMULSIONS PRODUCED THEREBY

摘要

PROCESS OF PREPARING A TABULAR GRAIN SILVER BROMOIODIDE EMULSION AND EMULSIONS PRODUCED THEREBY A process is disclosed for the preparation of a tabular grain silver bromoiodide emulsion in which silver bromoiodide laminae are formed on the major faces of the tabular grains. The sensitivity of the emulsion as a function of pressure applied is rendered more nearly constant by forming the silver bromoiodide laminae on the major faces of the tabular grains within a pAg and temperature range defined by Curve A in Figure 1. The laminae are formed by first precipitating iodide as a silver salt at peripheral sites on the tabular grains and then precipitating silver bromoiodide onto the major faces of the host tabular grains with the primary source of iodide being the previously deposited iodide. The emulsions produced exhibit high sensitivity to exposing radiation and reduced sensitivity to localized pressure.