Tabular grain emulsions containing laminar halide strata
US5132203A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Mar 11, 1991 |
| Grant date | Jul 21, 1992 |
| Priority date | — |
| Expiry date | Mar 11, 2011 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2001/0854
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
Photographic emulsions are disclosed comprised of radiation sensitive silver iodobromide grains, at least 50 percent of the total projected area of said silver iodobromide grains being accounted for by tabular grains exhibiting a mean tabularity of greater than 5, at least 10 percent of which are comprised of two opposed parallel major crystal faces, a host stratum having an iodide content of at least 4 mole percent, and laminar strata containing less than 2 mole percent iodide interposed between said host stratum and said opposed major crystal faces. The emulsions are characterized in that each of the laminar strata is comprised of a surface layer forming one of the major surfaces and having a thickness in the range of from 20 to 350 .ANG. and a subsurface layer located immediately beneath and in contact with the surface layer containing a hexacoordination complex of a Group VIII period 4 or 5 metal and at least three cyanide ligands.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.