Patent ID: 6048683
Filing Date: 2000-04-11
Classification: G03C

Abstract:
A method of manufacturing radiation-sensitive emulsions containing regular grains having six {100} crystal faces which extend to projected peripheral edges of the grain viewed normal to the {100} crystal faces, comprised of(a) creating a first population of silver halide grains in a stirred aqueous dispersing medium,(b) producing a second population of silver halide grains in the stirred aqueous dispersing medium by simultaneously introducing a silver salt solution and a halide salt solution into the dispersing medium,(c) while continuing stirring, simultaneously halting introduction of the silver salt solution and the halide salt solution to dissolve the second grain population, and(d) repeating steps (b) and (c) until the first grain population has increased to a selected larger size,WHEREIN(1) the halide salt solution is chosen to form silver halide grains containing greater than 50 mole percent chloride, based on silver, and(2) steps (a) through (d) are performed with a thioether ripening agent in the dispersing medium,the silver halide grains formed exhibit an average grain roundness coefficient n in the range of from 2 to less than 15,n satisfying the formula:x.sup.n +y.sup.n =R.sup.nin whichR is any vector extending from the center of a {100} crystal face of a grain to the projected peripheral edge of the grain viewed normal to the {100} crystal face;x is an X axis coordinate of R;y is a Y axis coordinate of R; andX and Y are mutually perpendicular axes in the plane of the {100} crystal face.