Ultrathin tabular grain emulsions containing speed-granularity enhancements
US5503971A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 26, 1994 |
| Grant date | Apr 2, 1996 |
| Priority date | — |
| Expiry date | Aug 26, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C1/46
- 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 70 mole percent bromide and at least 0.25 mole percent iodide, based on silver, (c) accounting for greater than 90 percent of total grain projected area, (d) exhibiting an average equivalent circular diameter of at least 0.7 .mu.m, (e) exhibiting an average thickness of less than 0.07 .mu.m, and (f) having latent image forming chemical sensitization sites on the surfaces of the tabular grains, are spectrally sensitized. The speed-granularity relationship of the emulsion is improved by employing in forming the surface chemical sensitization sites at least one silver salt epitaxially located on tabular grain surface sites that contain increased iodide concentrations. 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 …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.