Photographic materials with improved image tone
AssigneeImation Corp.
InventorsJulian M. Wallis, Robert J. D. Nairne, Alexis Zinn-Warner
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Abstract
A silver halide emulsion of average grain size 0.2 .mu.m or less comprising silver halide grains having a core and an outer shell, the core comprising at least 85 mol % of the total silver halide content of the grain and at least 50 mol % of the silver halide in the core being silver bromide, and the outer shell comprising silver halide of which greater than 50 mol % is silver chloride; the emulsion either containing no rhodium dopant, or containing rhodium dopant such that the concentration of said dopant is at least as great in the core as in the shell.
Claims10
A silver halide emulsion of average grain size 0.2 .mu.m or less comprising:
- (a) silver halide grains having a core and an outer shell, wherein the core comprises at least 85 mole % of the total silver halide content of the grain, at least 50 mole % of the silver halide in the core is silver bromide, and the outer shell comprises silver halide of which greater than 50 mol % is silver chloride;
- and
- (b) a toning agent comprising a compound of formula I or II:
- ##STR3## wherein:
- R.sup.1 and R.sup.2 independently represent the atoms selected from C, N, O and S necessary to complete a 5, 6, or 7 membered ring;
- R.sup.3 and R.sup.4 independently represent H, alkyl or aryl groups, or together represent the atoms selected from C, N, O and S necessary to complete a 5, 6 or 7 membered cyclic ring but are not both H;
- R.sup.5 and R.sup.6 independently represent H or alkyl groups, or together represent the atoms selected from C, N, O and S necessary to complete a 5, 6 or 7 membered ring;
- X represents a bond or a divalent linking group;
- each Y may be the same or different and is selected from the group consisting of O, NR.sup.7, S, and Se, where R.sup.7 is H or alkyl of up to 5 carbon atoms;
- and
- Z is S or Se.
Dependencies are inferred from the claim text.