Yellow dye-containing developing composition and its use in two-stage processing of roomlight handleable black-and-white photographic elements
US5942378A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 18, 1998 |
| Grant date | Aug 24, 1999 |
| Priority date | — |
| Expiry date | May 18, 2018 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/52
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Black-and-white elements, such as radiographic films, can be processed in roomlight because the developing composition includes a water-soluble colorant. Such colorants are water-soluble dyes that have a maximum absorption wavelength of from about 350 to about 500 nm. Processing is carried out by processing the exposed element using a two-stage process in the same processing container. In the first stage, development is initiated with an opaque developing composition having a pH of from about 10 to about 12.5, and comprising an appropriate black-and-white developing agent, a yellow colorant, and a sulfite. After an appropriate time, a fixing agent (other than a sulfite) is introduced into the processing container to begin simultaneous development and fixing. The entire process in quite rapid, that is less than 90 seconds.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.