Patent ID: 6136524
Filing Date: 2000-10-24
Classification: G03C

Abstract:
Method for preparing a light-sensitive silver halide photographic emulsion comprising performing at least three distinct precipitation steps in an aqueous medium in a reaction vessel, followed by desalting by means of flocculation and washing or by means of ultrafiltration, said emulsion comprising a colloidally stabilizing binder and {100} tabular silver halide grains containing at least 50 mole % of silver chloride, wherein at least 70% by number of all grains is provided by said tabular grains, exhibiting an average aspect ratio of at least 5 and an average equivalent circular grain diameter of at least 0.3 .mu.m, wherein said tabular grains have an average thickness of less than 0.25 .mu.m for at least 75% by number of all tabular grains;said three distinct precipitation steps being a nucleation step, a first and a second growth step,said method being further characterized by introducing in the said reaction vessel after the first growth step a polyoxyalkylene block-copolymer according to the formula (I) ##STR2## wherein said block-copolymer contains, besides an ethylenediamine unit as tetravalent linking unit, at least three terminal hydrophilic polyoxyethylene groups and not more than one terminal hydrophobic polyoxypropylene block unit.