Method and apparatus for altering the pH of a photographic developing solution
US5670303A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 28, 1995 |
| Grant date | Sep 23, 1997 |
| Priority date | — |
| Expiry date | Aug 28, 2015 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03C5/263
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A method for altering the pH of a photographic developing solution comprises altering the hydroxide ion concentration of the solution electrolytically. The method may be employed in photographic processing apparatus comprising a photographic development stage in which a photographic material to be processed is treated with a photographic developing solution wherein the apparatus comprises means for electrolytically altering the hydroxide ion concentration of the developing solution and means for controlling the operation of electrolytically altering the hydroxide ion concentration based on the change of hydroxide ion concentration in use.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.