Formation of tabular silver halide emulsions utilizing high pH digestion
US5013641A · kind A · utility
8Cited by
16References
22Claims
0Family size
Assignee
Inventors
Key dates
| Filing date | Dec 19, 1989 |
| Grant date | May 7, 1991 |
| Priority date | — |
| Expiry date | Dec 19, 2009 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C2200/44
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
The invention is generally accomplished by providing a tabular silver halide emulsion formation process in which the pH is controlled to greater than 9 by the addition of an alkali base prior to digesting to form uniform nucleated silver bromide particles. In a particularly preferred process the emulsion is adjusted to a pH greater than 9 by the use of sodium hydroxide, digestion takes place in between 3 and 7 minutes, and the emulsion making is completed in less than 100 minutes without the use of ammonium hydroxide. The emulsions formed are suitable for x-ray films and produce the image tone required by radiologists.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.