Radiation imagery chemistry: process – composition – or product th – Color imaging process
Reexamination Certificate
2000-11-03
2002-05-07
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Color imaging process
Reexamination Certificate
active
06383726
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a method for formulating a photographic developer composition using rapid processing of silver halide color negative films and process conditions to optimize developed images for digital manipulation to provide color display images with desired aim tone and color reproduction and photographic developer compositions formulated therefrom.
BACKGROUND OF THE INVENTION
Production of photographic color images from light sensitive materials basically consists of two processes. First, color negative images are generated by light exposure of camera speed light sensitive films, that are sometimes called “originating” elements because the images are originated therein by the film user (that is, “picture taker”). These negative images are then used to generate positive images in light sensitive materials. These latter materials are sometimes known as “display” elements and the resulting images may be known as “prints” when coated on reflective supports or “films” when coated on nonreflective supports.
The light sensitive materials are processed in automated processing machines through several steps and processing solutions to provide the necessary display images. Traditionally, this service has required a day or more to provide the customer with the desired prints. In recent years, customers have wanted faster service, and in some locations, the time to deliver this service has been reduced to within an hour. Reducing the processing time to within a few minutes is the ultimate desire in the industry. To do this, each step must be shortened.
Reduction in processing time of the “display” elements or color photographic papers has been facilitated by a number of recent innovations, including the use of predominantly silver chloride emulsions in the elements, and various modifications in the processing solutions and conditions so that each processing step is shortened. In some processes, the total time can be reduced to less than two minutes, and even less than 90 seconds.
Color negative films generally comprise little or no silver chloride in their emulsions, and have silver bromide as the predominant silver halide. More typically, the emulsions are silver bromoiodide emulsions with silver iodide levels up to several mol percent. Such films have required these types of emulsions because emulsions containing high silver chloride have generally had insufficient light sensitivity to be used as camera speed materials although they have the advantage of being rapidly processed without major changes to the color developer solution.
To shorten the processing time, specifically the color development time, of films containing silver bromoiodide emulsions, more active color developer solutions are needed. Various attempts have been made to increase color developer activity by increasing the pH, increasing the color developing agent concentration, decreasing the halide ion concentration, or increasing temperature. However, when these changes are made, the stability of the solution and the photographic image quality are often diminished.
For example, when the development temperature is increased from the conventional 37.8° C., and the color developer solution is held (or used) in the processing tanks for extended periods of times, silver bromoiodide elements processed with such solutions often exhibit unacceptably high density in the unexposed areas of the elements, that is unacceptably high Dmin.
Keeping of processing solutions for extended periods of time at high temperature for use in rapid high temperature color development of silver bromoiodide films has been accomplished by the use of a specific hydroxylamine antioxidant, as described in U.S. Ser. No. 08/590,241 (filed Jan. 23, 1996, by Cole).
Various methods have been proposed for overcoming problems encountered in processing high chloride silver halide emulsion-containing elements, but little has been done to address the problems for rapid processing of silver bromoiodide elements. For example, novel antioxidants have been developed to stabilize developer solutions (e.g., U.S. Pat. No. 4,897,339 of Andoh et al, U.S. Pat. No. 4,906,554 of Ishikawa et al, and U.S. Pat. No. 5,094,937 of Morimoto). High silver chloride emulsions have been doped with iridium compounds, as described in EP-A-0 488 737. Dyes have been developed to eliminate dye remnants from rapid processing as described in U.S. Pat. No. 5,153,112 of Yoshida et al. Novel color developing agents have been proposed for rapid development as described in U.S. Pat. No. 5,278,034 of Ohki et al.
All of the foregoing methods have been designed for processing high silver chloride photographic papers, and have not been shown to be effective in processing color negative silver bromoiodide films.
U.S. Pat. No. 5,344,750 (Fujimoto et al) describes a method for processing elements containing silver iodobromide emulsions that is allegedly rapid, including color development for 40-90 seconds. The potential problems of low sensitivity and high fog in rapidly developed elements is asserted to be overcome by using a color development temperature and an amount of color developing agent and bromide ion in the color developer that are determined by certain mathematical relationships. That is, the amount of color developing agent and bromide ion is considered to be related, and the development temperature and bromide ion concentration are related, both relationships being expressed in mathematical equations.
It has been found, however, that even when the relationships described in U.S. Pat. No. 5,344,750 are followed and color negative films are color developed in short times (less than 90 seconds), the color balance of the three color records cannot be maintained through a useful exposure range. By “color balance” is meant the display image, produced from a neutral exposure of a color negative image, will have a neutral color rendition throughout the useful exposure range. The color record imbalance is caused by the difficulty of getting sufficient development in the color record next to the support without forcing the topmost color record to be overdeveloped, resulting in high fog, contrast or Dmax. This color imbalance in the color records of a multilayer photographic color film cannot be corrected using conventional optical printing of the color negative onto a color display element. Thus, very short development times of the color negative films cannot readily provide negative images in the “originating” color negative film capable of providing display images having acceptable tone scale and color reproduction. This limitation is a serious obstacle to the development of imaging systems with very rapid access to the final photographic print.
U.S. Pat. No. 5,455,146 (Nishikawa et al) describes a method for forming color images in photographic elements containing silver iodobromide emulsions that is allegedly rapid and includes color development for 30-90 seconds. The potential problems of gamma imbalance are asserted to be overcome by controlling the morphology of the light sensitive silver halide emulsion grains, the thickness and swell rate of the photographic film, and the ratio of 2-equivalent color couplers to total couplers in the red-sensitive silver halide emulsion layer. However, the methods described in this patent require a color negative film to be specifically constructed with the noted features to correct gamma imbalance, but they do not correct the color imbalance produced by rapidly developing commercially available color negative films that do not have the noted features. In other words, the method of gamma correction requires a specific film and cannot be applied to any film on the market.
After a color negative film has been chemically processed in the manner described above, it can be scanned to create a digital representation of the image. The most common approach to scanning an image is to record the transmission of a light beam, point-by-point or line-by-line. In color photography, blue, green and red scanning beams are modulated
Arcus Robert A.
Hall Jeffrey L.
Weldy John A.
Eastman Kodak Company
Le Hoa Van
Meeks Roberts Sarah
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