Photographic silver halide developer composition and process for forming photographic silver images
US5998110A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Nov 6, 1997 |
| Grant date | Dec 7, 1999 |
| Priority date | — |
| Expiry date | Nov 6, 2017 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/15
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A black-and-white aqueous alkaline photographic developer composition is described which is free of dihydroxybenzene developing agent and comprises a p-aminophenol primary developing agent and an auxiliary superadditive 3-pyrazolidone developing agent, wherein the p-aminophenol primary developing agent is represented by the following formula: ##STR1## wherein R.sub.1, and R.sub.2, which may be the same or different, each represents a hydrogen atom, an alkyl group, or R.sub.1, and R.sub.2 together represent the carbon atoms required to complete a 5-membered saturated ring, R.sub.3 represents a hydrogen atom, an alkyl group or an alkoxy group, n represents 0 or 1, and HX represents HCl or 1/2 H.sub.2 SO.sub.4. A process for forming a black-and-white photographic silver image comprising developing a silver halide photographic element with the black-and-white aqueous alkaline photographic developer composition is also described.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.