Image toners for silver halide photographic films
US5922527A · kind A · utility
2Cited by
10References
19Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Jul 15, 1997 |
| Grant date | Jul 13, 1999 |
| Priority date | — |
| Expiry date | Jul 15, 2017 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10S430/166
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A black-and-white, negative-acting, silver halide emulsion is described which gives improved image tone when used in a photographic element. The toning agents are based on dithio-substituted compounds having the following general structures: ##STR1## where R.sub.1 and R.sub.2, independently, are selected from the group consisting of alkyl, aryl and heterocyclic groups, or R.sub.1 and R.sub.2 together complete a ring; PA1 n and m are integers from 1 to 5; Y is a hydrogen; R.sub.3 is a hydrogen or alkyl group; PA1 and X is selected from the group consisting of O, S, N--OH and N--N(R).sub.2, where R is a hydrogen or alkyl group.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.