Classifications

• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/29—Development processes or agents therefor
  • G03C5/31—Regeneration; Replenishers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
  • G03C7/00—Multicolour photographic processes or agents therefor; Regeneration of such processing agents; Photosensitive materials for multicolour processes
  • G03C7/30—Colour processes using colour-coupling substances; Materials therefor; Preparing or processing such materials
  • G03C7/44—Regeneration; Replenishers
• • G—PHYSICS
  • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
  • G03D—APPARATUS FOR PROCESSING EXPOSED PHOTOGRAPHIC MATERIALS; ACCESSORIES THEREFOR
  • G03D3/00—Liquid processing apparatus involving immersion; Washing apparatus involving immersion
  • G03D3/02—Details of liquid circulation
  • G03D3/06—Liquid supply; Liquid circulation outside tanks
  • G03D3/065—Liquid supply; Liquid circulation outside tanks replenishment or recovery apparatus

Definitions

• the present invention relates to the replenishment of chemical solutions used in the processing of photographic materials.
• GB-A2111726 describes a system for controlling the addition of replenisher to a bath in which light-sensitive media are being processed.
• the signal controlling the rate of addition of replenisher chemicals is derived from the area of the light-sensitive media which has been scanned by a laser exposing device.
• a method of controlling the rate of replenishment of chemical solutions used in photographic processing apparatus including photographic printing apparatus for copying an object on to photographic material, the method being characterized by the steps of deriving a signal which is related to the exposure given to the photographic material, and using the signal to control the replenishment rate of the processing solutions.
• the derived signal produces a replenishment rate which is directly related to the amount of image-producing substances formed on the photographic material after development of an image of the object.
• the derived signal produces a replenishment rate which exactly balances the chemicals depleted in processing the photographic material.
• Photographic processors are normally set up so that the replenishment rate exactly compensates for the chemicals used in processing paper which has been exposed to an predefined average grey level.
• This grey level is intended to simulate the amount of dye produced on a print made from the average (population centre) customer negative. It is usual to calibrate the printer with such a population centre negative which is printed to produce a grey print at the average grey level. The printer is adjusted so that the correct density is produced on the grey print.
• a colour photographic material has three image forming layers: the cyan, magenta and yellow. Light is projected through the film on to the paper to form a latent image which is rendered visible by the processing solutions.
• Dye is formed by the reaction of developer molecules which have been oxidised by the reduction of silver halide to silver metal and halogen gas, with coupler molecules in the paper.
• the equivalence of a dye is the amount of oxidised developer molecules which is needed to form one molecule of the dye.
• the dyes used are typically 2 and 4 equivalent. In practice, the measured equivalence of a dye may be more than this because not all oxidised developer molecules are converted to dye. Some molecules are lost due to other reactions and processes. Furthermore, the amount of oxidised developer molecules that are lost may vary according to the amount of dye which has already been formed on the paper at any point in the development cycle.
• R0 is the average amount of replenisher which is added per square foot of paper.
• R0 k[e c (c0)+e m (m0)+e y (y0)+j(t)]+K (2)
• K0 is a known quantity and is a recommended figure by manufacturers of photographic products. For machines with large tank volumes, there will be as many prints with dye amounts less than the average than with dye amounts above the average. Developer efficiency is therefore unaffected by these fluctuations in print dye amount. Small volume machines, however, would benefit from being able to calculate ⁇ R and vary the replenisher rates accordingly. There are several ways of calculating ⁇ R, but none is perfectly accurate.
• a '+3 button' correction increments the time by 1.19 x 1.19 x 1.19 or 1.68.
• a '-4 button' change decreases the time by 1.19 x 1.19 x 1.19 x 1.19 or 2 (a halving of the time).
• the exact increment is usually variable and can be set up by the user.
• More sophisticated printer algorithms may permit much smaller increments in density and colour balance. In these cases, it may be possible to perform a calculation to get values for ⁇ R rather than having to perform many experimental determinations. Again, the exact details of the calculation will vary from machine to machine so the general outline will be explained below, where the assumption is made that an average measurement of the negative transmittance has been made (rather than discrete measurements at many places on the negative).
• the next step is to convert from reflection density to transmission density using another well known relation (see Williams and Klapper, Journal of the Optical Society of America, 1953, volume 43, page 595). It is now possible to obtain relative dye amounts on the print to a good approximation by taking the ratio of the transmission densities of the print in question, T Di , to the transmission density of the calibration print, T0 Di .
• T Di transmission densities of the print in question
• T0 Di the transmission density of the calibration print
• Equation (7) we have a relationship between the correction to the replenishment rate and the transmission density of the print, which is a function of E i , the exposure given to the print.
• the functional relationship between T Di and E i is found from a knowledge of the paper's R D - log(E) curve, and the R D /T D curve as is described in detail by Williams and Klapper mentioned above. It is preferable to combine these two curves into a single function, which may be a table of pairs of values relating E i and T Di . Intermediate points may, of course, be found by interpolation.
• the ⁇ R i term will normally be a small correction to R i and therefore a high degree of accuracy is not required to establish the relationship between E i and T Di .
• Photofinishing printers work in one of three ways. Some expose one print at a time and immediately send each exposed print to a processing machine. Others expose small batches of prints (typically between five and thirty prints) which are sent in one long length to the processing machine. These first two types of printer are normally found in minilabs where the printer is directly connected to a processor. There are still other types of printer which expose very large batches of prints, typically many hundreds, on to long rolls of paper before being taken uncut to a separate processing machine. These types of printers are normally found in high volume photofinishing establishments.
• the replenishment data would need to be recorded on a magnetic storage medium, such as a floppy disc.
• a magnetic storage medium such as a floppy disc.
• the floppy disc would then be loaded into the paper processor's own floppy disc drive.
• the paper processor equipped with a microprocessor controlled replenishment system, would access the replenishment data via its microprocessor as the roll of photographic paper is being processed in a developer. After a fixed number of prints have entered the developer, for example ten, an amount of replenisher would be added to the developer bath and an equal amount of developer drained off. The amount added would correspond to the sum of the replenisher amounts for the particular ten prints in the developer.
• the replenishment information for each print may also be recorded on the print itself by means of a machine-readable code applied to the back of the print.
• the information may be encoded as a series of punched holes between prints.
• Photographic printers which only use discrete photocells for determining exposure measure only the average transmittance of a negative.
• a subject comprising a white spot against a black background would print as a black spot on a white background.
• the black spot would have reached the maximum density the photographic paper could give.
• the amount of dye in the spot would therefore be less than that expected from a calculation based on the average transmittance of the negative. Consequently, the calculated amount of replenishment required for that print would be too great.
• a scanning device for example a charge-coupled device having a 30 by 20 array, would yield 600 measurements of the transmittance of the negative. Areas of low density on the negative which would give an area of D max on the print could be recognized as such, by using the paper's R D - log(E) curve. The dye amounts formed at each of the 600 areas could be added together to give an accurate calculation of the total dye amount formed on the print.
• the present invention has the advantage that it overcomes the problem of incorrect chemical replenishment, thus reducing sensitometric drift, maintaining quality and therefore saving money.
• the present invention would be particularly suited to a small photofinishing operation such as a mini-lab where small chemical volumes in the processing tanks increase the susceptibility of the photographic processor to the effects of incorrect replenishment. Furthermore, for the small photofinishing operation, the relatively low hardware cost required to incorporate the present invention in a printer-processor pair is an added advantage. In addition, the need for a storage medium on which to retain the dye amounts calculated for the prints from a given roll of negatives during printing would be eliminated as the microprocessors in both the printer and the processor would be able to transfer the data between them.
• the invention is particularly suited to the replenishment of photographic developers, but could be used with any apparatus where the replenishment rate is a function of the image density.

Landscapes

• Physics & Mathematics (AREA)
• General Physics & Mathematics (AREA)
• Photographic Processing Devices Using Wet Methods (AREA)
• Silver Salt Photography Or Processing Solution Therefor (AREA)
• Nitrogen Condensed Heterocyclic Rings (AREA)
• Control Of Exposure In Printing And Copying (AREA)
• Color Image Communication Systems (AREA)
• Photosensitive Polymer And Photoresist Processing (AREA)
• Photographic Developing Apparatuses (AREA)

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• 1989
  • 1989-02-01 GB GB898902186A patent/GB8902186D0/en active Pending
• 1990
  • 1990-01-31 MY MYPI90000157A patent/MY104823A/en unknown
  • 1990-02-01 DE DE69009741T patent/DE69009741T2/de not_active Expired - Fee Related
  • 1990-02-01 ES ES90902349T patent/ES2054339T3/es not_active Expired - Lifetime
  • 1990-02-01 EP EP90301062A patent/EP0381502A1/fr active Pending
  • 1990-02-01 AT AT90902349T patent/ATE107050T1/de not_active IP Right Cessation
  • 1990-02-01 EP EP90902349A patent/EP0456684B1/fr not_active Expired - Lifetime
  • 1990-02-01 WO PCT/GB1990/000162 patent/WO1990008979A1/fr active IP Right Grant
  • 1990-02-01 DK DK90902349.1T patent/DK0456684T3/da active
  • 1990-02-01 AU AU50218/90A patent/AU627551B2/en not_active Ceased
  • 1990-02-01 CA CA002046626A patent/CA2046626A1/fr not_active Abandoned
  • 1990-02-01 KR KR1019910700818A patent/KR920701866A/ko active IP Right Grant
  • 1990-02-01 JP JP2502692A patent/JP2930407B2/ja not_active Expired - Fee Related

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