High speed emulsions exhibiting superior speed-granularity relationships
US5612176A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Jan 26, 1996 |
| Grant date | Mar 18, 1997 |
| Priority date | — |
| Expiry date | Jan 26, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2001/091
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Spectrally sensitized tabular grain emulsions are disclosed exhibiting increased speeds and speed-granularity relationships superior to those of conventional emulsions of the same average grain sizes. The tabular grains have {111} major faces, contain greater than 70 mole percent bromide and from 0.25 to 10 mole percent iodide, based on silver, exhibit an average aspect ratio of greater than 50 and an average equivalent circular diameter of >10 micrometers, account for greater than 90 percent of total grain projected area, and have latent image forming chemical sensitization sites on their surfaces including epitaxially deposited silver halide protrusions of a face centered cubic rock salt crystal lattice structure forming epitaxial junctions with the tabular grains. The protrusions are restricted to those portions of the tabular grains (a) located nearest peripheral edges of and (b) accounting for less than 50 percent of the {111} major faces of the tabular grains, contain a silver chloride concentration at least 10 mole percent higher than that of the tabular grains, and include a higher iodide concentration than those portions of the tabular grains extending between the {111} ma…
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