High bromide ultrathin tabular emulsions improved by peptizer modification
US5667955A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jun 12, 1996 |
| Grant date | Sep 16, 1997 |
| Priority date | — |
| Expiry date | Jun 12, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/03
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An improved spectrally sensitized ultrathin tabular grain emulsion is disclosed in which tabular grains (a) having {111} major faces, (b) containing greater than 50 mole percent bromide, based on silver, (c) accounting for greater than 70 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, and (e) exhibiting an average thickness of less than 0.07 .mu.m, show an enhanced capability for chemical sensitization by reason of employing an oxidized cationic starch as a peptizer. A photographic element is disclosed comprised of a support, a first silver halide emulsion layer coated on the support and sensitized to produce a photographic record when exposed to specular light within the minus blue visible wavelength region of from 500 to 700 nm, a second silver halide emulsion layer capable of producing a second photographic record coated over the first silver halide emulsion layer to receive specular minus blue light intended for the exposure of the first silver halide emulsion layer, the second silver halide emulsion layer being capable of acting as a transmission medium for the delivery of at least a portion of the minus blu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.