Dye image reversal processes and image transfer film units
US4258117A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 1, 1979 |
| Grant date | Mar 24, 1981 |
| Priority date | — |
| Expiry date | Nov 1, 1999 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C5/50
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method is disclosed of photographically processing a negative-working imagewise exposed silver halide photographic element to produce a reversal dye image comprising (a) developing the imagewise exposed silver halide with an electron transfer agent to produce oxidized electron transfer agent which reacts with a competing oxidizable substance and (b) developing silver halide remaining with the electron transfer agent in the presence of a dye image providing compound capable, after the competing oxidizable substance has been depleted, of reacting with the oxidized electron transfer agent to produce a reversal dye image. Image transfer film units are disclosed useful in the practice of this method. Such film units include those containing in addition to the competing oxidizable substance and initially immobile dye image providing compound a layer containing additional silver halide and a scavenger separating the additional silver halide from the immobile dye image providing compound.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.