Color diffusion transfer element with auxillary neutralizing layer comprising cellulose acetate
US4916044A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 29, 1987 |
| Grant date | Apr 10, 1990 |
| Priority date | — |
| Expiry date | Dec 29, 2007 |
Classification
- Technology area (CPC Y)Emerging Cross-Sectional Technologies
- CPC primaryY10T428/31971
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A color photographic element for use in color diffusion transfer photography comprised of a lightsensitive dye release and receiving sheet and a cover sheet, wherein development, dye release and dye transfer occur in the presence of an alkaline processing solution, and wherein the cover sheet is provided with a neutralizing system which causes neutralization by an alkaline processing solution to proceed by at least a first and a second stage, wherein the first stage is characterized in that neutralization (lowering) of the pH of an alkaline processing solution occurs to the extent to interrupt development and dye release reactions but at which the transfer of a dye for forming a transfer image can continue, and a second stage at which the pH of the processing solution is gradually lowered to a final value which is stably maintained over prolonged storage, the photographic element characterized in that the neutralizing system comprises at least a neutralizing layer, a 2nd neutralization timing layer, an auxiliary neutralizing layer, and a 1st neutralization timing layer as viewed from the support side, and that said auxiliary neutralizing layer contains 5 to 60% by weight of a cellu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.