Dainippon Ink and Chemicals, Incorporated

Polychrome Corporation

John Pilot

Burton H Waxman

Yasuhiko Kojima

Novel dot enhancing compositions are disclosed for use in high contrast negative-working image-forming systems. The compositions include compounds of the general formula: ##STR1## wherein R.sub.1 is an aromatic group, A is a substituted or unsubstituted aromatic nucleus, and the two carboxyl groups specifically depicted in general formula (I) are each bound to a different carbon atom of said aromatic nucleus. The dot enhancing compositions may be incorporated into a silver halide photographic emulsion or into another hydrophilic colloid layer of a photographic material, or into a developing solution or, alternatively, into both. The dot enhancers of the invention improve density and contrast of images formed, as well as providing a harder, smoother, better formed dot for use in letter press and offset lithography.

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Carteret, NJ, United States of America

John Pilot