Photographic silver halide emulsion prodn. - by continuous multistage method using series of reactors with batch operation giving reproducible emulsion

摘要

Prodn. of photographic Ag halide (AgX) emulsions is carried out in stages, by a batch process in reactors of medium size, as follows : (a) an aq. Ag salt soln. and an aq. halide salt soln. are reacted in reactor 1, forming a AgX emulsion contg. AgX grains, and (b) this emulsion is transferred to reactor 2, where (c) an aq. Ag salt soln. and an aq. halide salt soln. or fine AgX grains with an average dia. of max. 0.1 micron is added to grow AgX on the AgX grains; then (d) the emulsion is transferred to reactor 3 and (e) subjected to desalination, chemical ripening and/or chemical sensitisation. USE/ADVANTAGE - The process is suitable for mass prodn., on the large or small scale, and gives an emulsion with narrow grain size distribution and the required average grain size, with good reproducibility.