Patent ID: 6043019
Filing Date: 2000-03-28
Classification: G03C

Abstract:
A method of manufacturing a radiation-sensitive tabular grain emulsion comprised of(a) providing in a stirred reaction vessel a dispersing medium containing a stoichiometric excess of bromide ions and a host tabular grain emulsion comprising greater than 50 mole percent bromide, based on silver, and a speed enhancing amount of iodide and(b) then precipitating silver bromide onto grains of the host tabular grain emulsion,WHEREIN, in step (b),(1) introducing a silver salt solution into the dispersing medium at a rate sufficient to create a new grain population,(2) halting introduction of the silver salt solution for a time sufficient to allow the new grain population to be dissolved by ripening with silver and bromide ions released from the new grain population being precipitated onto the grains of the host tabular grain emulsion, and(3) repeating steps (1) and (2) from 3 to 20 times until silver bromide deposited onto the grains of the host tabular grain emulsion amounts to from 5 to 50 percent of total silver forming the radiation-sensitive tabular grain emulsion.