Photographic elements with tetra-nuclear merocyanine sensitizers
US5563021A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jun 7, 1995 |
| Grant date | Oct 8, 1996 |
| Priority date | — |
| Expiry date | Jun 7, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/061
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photographic element comprising a light sensitive silver halide emulsion sensitized with a dye of formula (I) and a nucleating agent or amine booster associated with the silver halide emulsion: ##STR1## wherein: R.sub.3 is an alkyl group, alkenyl group, or aryl group PA1 R.sub.4 and R.sub.5 are each hydrogen, an alkyl group, alkenyl or aryl group; PA1 R.sub.6, R.sub.7 and R.sub.8 are, independently, an alkyl group, alkenyl group, aryl group, or H; PA1 the dye has at least three acid or acid salt substituents; and PA1 each L independently represents a methine group; PA1 p is 0 or 1; PA1 Z.sub.1 represents the atoms necessary to complete a 5- or 6-membered heterocyclic ring group; PA1 (X).sub.n represents counterions as needed to balance the charge on the molecule. The present invention also provides a process for forming a high contrast photographic image on a photographic element having a light sensitive silver halide emulsion sensitized with a dye of formula (I). The process comprises developing such a photographic element in the presence of a hydrazine compound and an amine booster.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.