Radiation imagery chemistry: process – composition – or product th – Regenerating image processing composition – Developer
Patent
1993-05-07
1995-01-10
Bowers, Jr., Charles L.
Radiation imagery chemistry: process, composition, or product th
Regenerating image processing composition
Developer
430398, 430373, 430380, 430943, 354322, 354323, 354324, 354331, 354332, G03C 518, G03C 526, G03C 700, G03C 746
Patent
active
053806271
DESCRIPTION:
BRIEF SUMMARY
This invention relates to a method of processing a photographic silver halide material and particularly to the dye image-forming step.
Photographic silver halide colour materials comprise at least one silver halide emulsion layer and, associated therewith, a dye-forming colour coupler. On development with a colour developing agent, the oxidised colour developing agent couples with the coupler to form image dye.
Many processing machines provide replenishment of the processing solutions to replace active ingredients which have been consumed in the process or that have deteriorated due to reactions with, for example, oxygen in the air.
When colour development takes place silver halide in the photographic material is reduced releasing halide ions into the solution. These have a inhibiting effect on the dye image-forming process and most colour developers are designed to operate with a particular level of halide in the solution. This is particularly true in a redox amplification system using hydrogen peroxide. It is usual to maintain a constant level of halide ion to ensure uniform imageforming performance.
In the abstract of Japanese patent application 55/117144 a system is proposed for reducing the concentration of halide ions as development progresses by a system of multiple tanks (or troughs) separated by halide ion removing baths. It is said to utilise developing agents with high efficiency, provide rapid processing and reduce staining and fogging. Such a system is, however, over complicated having 2-5 developing troughs and 1-4 halide-removing baths and would be very difficult to implement, especially if it was a replenished system.
The present invention provides a practical method of maintaining controlled concentration profiles for a processing bath component, for example halide ions, in a single processing tank.
According to the present invention there is provided a method of processing an imagewise exposed photographic silver halide material in a system in which at least one processing step comprises transporting the material through a processing tank through which the processing solution (which is replenished when necessary) is recirculated characterized in that said processing step takes place in a single processing tank divided into at least two parts separated by a barrier through which the material passes but which reduces the mixing of the solutions in the neighbouring parts and in that each part is separately recirculated and replenished to maintain a different concentration of a processing bath component in the first or earlier part than the second or later part.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic of a prior art replenishment system for an RX developer/amplifier tank.
FIG. 2 is a plot of the uniform halide ion concentration throughout the tank of FIG. 1.
FIG. 3 is a schematic of a replenishment system according to the present invention.
FIG. 4 is a plot of the non-uniform halide ion concentration throughout the tank of FIG. 3.
The present invention may, in particular, be applied to the control of halide ion concentration in processing baths.
Although the remaining description is directed to the redox amplification processing of silver chloride colour papers it is specifically recognised that the present invention also has application to more conventional processes, for example conventional colour development. In such a case the developer-amplifier described hereinafter would be replaced by a colour developer.
The present method is particularly suitable for a redox amplification method of dye image formation. Redox amplification processes have been described, for example in British Specification Nos. 1,268,126, 1,399,481, 1,403,418 and 2,560,572. In such processes colour materials are developed to produce a silver image (which may contain only small amounts of silver) and then treated with a redox amplifying solution (or developer-amplifier) to form a dye image. The redox amplifying solution contains a reducing agent, for example a colour developing agent, and an oxidisi
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Abstract of Japanese Patent Specification JPA 55/117144 assigned to Konishiroku Photo KK, dated Sep. 9, 1980.
Bowers Jr. Charles L.
Eastman Kodak Company
Pasterczyk J.
Roberts Sarah Meeks
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