Process for the preparation of high chloride tabular grain emulsions (II)

Claim 1

A process of preparing a radiation sensitive high aspect ratio tabular grain emulsion, wherein tabular grains of less than 0.3 μm in thickness and an average aspect ratio of greater than 8:1 account for greater than 50 percent of the total grain projected area, said tabular grains containing at least 50 mole percent chloride, based on silver, comprising introducing silver ion into a gelatino-peptizer dispersing medium containing a stoichiometric excess of chloride ions with respect to the silver ions further characterized by a chloride ion concentration of less than 0.5 molar and a grain growth modifier of the formula: ##STR20## where Z 2 is --C(R 2 )═ or --N═; Z 3 is --C(R 3 )═ or --N═; Z 4 is --C(R 4 )═ or --N═; Z 5 is --C(R 5 )═ or --N═; Z 6 is --C(R 6 )═ or --N═; with the proviso that no more than one of Z 4 , Z 5 and Z 6 is --N═; R 2 is H, NH 2 or CH 3 ; R 3 , R 4 and R 5 are independently selected, R 3 and R 5 being hydrogen, hydroxy, halogen, amino or hydrocarbon and R 4 being hydrogen, halogen or hydrocarbon, each hydrocarbon moiety containing from 1 to 7 carbon atoms; and R 6 is H or NH 2 .