Limited dispersity epitaxially sensitized ultrathin tabular grain emulsions
US5726007A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Sep 30, 1996 |
| Grant date | Mar 10, 1998 |
| Priority date | — |
| Expiry date | Sep 30, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/03
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A photographic emulsion is disclosed comprised of coprecipitated radiation-sensitive silver halide grains containing greater than 70 mole percent bromide, based on silver, and exhibiting a coefficient of variation of less than 30 percent. Greater than 90 percent of total projected area of the grains is accounted for by tabular grains having {111} major faces, exhibiting a thickness of less than 0.07 .mu.m, and having latent image forming silver salt epitaxy chemical sensitization sites on their surfaces, and a dispersing medium that contains a grain dispersity reducing concentration of a polyalkylene oxide block copolymer surfactant comprised of two terminal lipophilic alkylene oxide block units linked by a hydrophilic alkylene oxide block unit accounting for from 4 to 96 percent of the molecular weight of the polymer. The emulsions offer unexpectedly low levels of minimum density and can be more easily manufactured as compared to conventional ultrathin tabular grain emulsions with comparably limited grain dispersity.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.