Method of production of emulsions with monodispersed silver halide distarch grains

摘要

The present invention relates to a process for preparing monodispersed tabular silver halide grain emulsions, said process comprising the following steps: (a) forming a population of silver halide nuclei in a dispersing medium having a pH lower than 3 and a pBr in the range of from 1 to 2, (b) ripening said population of silver halide nuclei in presence of a silver halide solvent, (c) performing a first growing of said silver halide nuclei at a pBr value in the range of from 1 to 2, and (d) performing a second growing of said silver halide nuclei at a value in the range of from 2 to 2.7. According to a preferred embodiment of the present invention a polyalkylene oxide-polyalkylsiloxane copolymer is present during at least one of the above mentioned steps (a) to (d). The process of the present invention enable the growth of monodispersed tabular silver halide grain emulsions having a reduced amount of non-conforming grains and a lower coefficient of variation (COV).