High-contrast photographic elements with enhanced safelight performance
US5372921A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 2, 1993 |
| Grant date | Dec 13, 1994 |
| Priority date | — |
| Expiry date | Nov 2, 2013 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/49
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A high-contrast room-light-handleable black-and-white silver halide photographic element that is especially useful in the field of graphic arts is comprised of a support, an imaging layer containing doped silver halide grains with a mean grain size of less than 0.12 micrometers, a print-out layer containing doped silver halide grains with a mean grain size in the range of from 0.14 to 0.4 micrometers, and a third set of doped silver halide grains with a mean grain size of less than 0.12 micrometers distributed within the print-out layer or within a separate safelight protection layer. Dopant levels are controlled so that the photographic speed of the imaging layer is higher than the photographic speed of the print-out layer and so that the photographic speed of the third set of silver halide grains is less than that of the imaging layer. The element utilizes very slow speed emulsions which render it capable of being handled in room light and is able to print-out a visible image on normal exposure and develop to full density upon being processed in conventional developing solutions.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.