Superhigh contrast negative image forming process
US5217842A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 18, 1991 |
| Grant date | Jun 8, 1993 |
| Priority date | — |
| Expiry date | Sep 18, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/067
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A process of forming superhigh-contrast negative images is disclosed. The process comprises the steps of imagewise exposing a substantially surface latent image-type silver halide photographic material which is spectrally sensitized with a sensitizing dye and then developing said photographic material with a developer, wherein said photographic material contains a heterocyclic thione compound and said developer comprises (a) an aminophenol derivative developing agent, (b) a reductone compound, (c) a quaternary ammonium salt, and (d) a compound represented by formula (I): ##STR1## wherein R.sub.1, R.sub.2 and R.sub.3, which may be the same or different, each represents a hydrogen atom, a nitro group, a halogen atom, or a cyano group, and wherein said development processing is carried out in the existence of at least one kind of a polyalkylene oxide or a derivative thereof. The process provides negative images of superhigh contrast having gamma over 10 substantially free from appearance of pepper.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.