Optical: systems and elements – Optical modulator – Light wave directional modulation
Patent
1992-07-21
1994-08-09
Rutledge, D.
Optical: systems and elements
Optical modulator
Light wave directional modulation
354324, G03D 1300, G03D 302
Patent
active
053371127
DESCRIPTION:
BRIEF SUMMARY
FIELD OF THE INVENTION
The present invention relates to automatic film processing devices for the processing of photographic material.
BACKGROUND OF THE INVENTION
Various kinds of processing machinery are available for processing negative film, for processing colour prints, for processing colour reversal film and for preparing reversal prints.
In general the process involves developing a silver image then oxidising the silver in a bleaching stage followed by removimg the silver in a fixing stage. These stages occur in all normal photographic processes, whether black and white, or colour and whether negative or reversal processing; although further stages will be required in the case of reversal processing, and dye coupling during development in the case of colour processing.
In automatic processing systems, ingredients are taken up in the various stages of processing, and therefore the various processing baths need replenishment of their constituents in order to keep them at the correct consistency.
Automatic replenishment systems have been proposed previously in which the strength of the developed dye image is measured and this is then used to determine the rate of replenishment of the various ingredients. U.S Pat. Nos. 4,057,818 and 3,554,109 describe such systems.
In these systems dye density is measured after the film is fully processed in order to assess the replenishment needs.
These methods therefore give rise to a degree of inaccuracy since the amount of dye in the final image is not necessarily a direct function of the total amount of developing agent consumed in forming the final image.
The present invention directs itself to this problem and aims to provide an improved method of assessing the replenishment need.
SUMMARY OF THE INVENTION
Accordingly the present invention provides an automatic film processing device for photographic materials including at least one developing station to develop an image including silver on a carrier substrate, and at least one station for bleaching and removing the silver to provide a fixed image on said carrier substrate, an infra red sensing device for measuring the need for replenishment and replenishment means for replenishment of developer chemicals in dependence on the measured need for replenishment, characterised in that the infra red sensing device is located at a position prior to removal of the silver and is arranged to measure the density of silver in the developed image on the carrier substrate in order to provide a measure of the replenishment need.
Accordingly the infra red sensing device will normally be provided immediately after the developing station and prior to the bleaching and fixing station or stations.
The measurement of silver can be used for control of replenishment of developer, bleacher and fixer; however replenishment of fixer can be more accurately controlled by measurement of silver halide.
Accordingly a second feature of the present invention is provision of a second infra red sensing device which is located to measure silver halide content-of said carrier substrate, and thereby to control replenishment of fixer. In such a case the first infra red sensing device controls replenishment of developer and bleacher chemicals.
The carrier substrate may be a negative or transparency film base or it may be a paper base for colour prints.
In the case of colour processing, measurement of the amount of developed silver in situ during development is particularly accurate since the amount of colour developing agent consumed and the amount of bromide ion released in the development reaction is proportional to the amount of silver developed. This means that the replenishment need for any film can be accurately assessed from the average developed silver level.
On the other hand in the prior art processes where dye density is measured, this measurement is less accurate because the dye to silver ratio can vary for different film types and from different manufacturers. The reason for this variation is that not all the oxidised colour developin
REFERENCES:
patent: 3462221 (1969-08-01), Tajima et al.
patent: 3515050 (1970-06-01), Attridge et al.
patent: 3554109 (1971-01-01), Street et al.
patent: 3680463 (1972-08-01), Attridge et al.
patent: 4881095 (1989-11-01), Shidara
Skye David A.
Twist Peter J.
Eastman Kodak Company
Pincelli Frank
Rutledge D.
LandOfFree
Automatic processing devices for processing photographic materia does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Automatic processing devices for processing photographic materia, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Automatic processing devices for processing photographic materia will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-219720