Photographic products and processes
US4891298A · kind A · utility
5Cited by
7References
30Claims
0Family size
Assignee
Inventor
Key dates
| Filing date | Oct 3, 1988 |
| Grant date | Jan 2, 1990 |
| Priority date | — |
| Expiry date | Oct 3, 2008 |
Classification
- Technology area (CPC C)Chemistry; Metallurgy
- CPC primaryC09B11/26
- WIPO fieldBasic materials chemistry
- WIPO sectorChemistry
Abstract
This invention relates to diffusion transfer photographic processes adapted to be performed in the presence of ambient light and to diffusion transfer products useful in such processes wherein a substantial increase in opacification in the red and near infrared region of the visible spectrum and a substantial increase in opacification in the blue and green region is achieved by employing certain alkyl-substituted phenanthrol/carboxynaphthol phthaleins as the light-absorbing, pH-sensitive optical filter agent for the longer wavelength region of the visible spectrum.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.