Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-11-03
2001-06-26
Le, Hoa Van (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S549000, C430S570000
Reexamination Certificate
active
06251578
ABSTRACT:
FIELD OF THE INVENTION
The instant invention relates to a silver halide emulsion prepared for use in the red sensitive layer unit of a color photographic element. The element is particularly suitable for scanning, electronic manipulations, and reconversion to a viewable form that accurately records light according to the human visual system.
DEFINITION OF TERMS
The term “E” is used to indicate exposure in lux-seconds.
The term “Status M density” is used to indicate image dye densities measured by a densitometer meeting photocell and filter specifications described in
SPSE Handbook of Photographic Science and Engineering
, W. Thomas, editor, John Wiley & Sons, New York, 1973, Section 15.4.2.6 Color Filters. The International Standard for Status M density is set out in “Photography—Density measurements—Part 3: Spectral conditions”, Ref. No. ISO 5/3-1984 (E).
The term “gamma” is employed to indicate the incremental increase in image density (&Dgr;D) produced by a corresponding incremental increase in log exposure (&Dgr;log E) and indicates the maximum gamma measured over an exposure range extending between a first characteristic curve reference point lying at a density of 0.15 above minimum density and a second characteristic curve reference point separated from the first reference point by 0.9 log E.
The term “coupler” indicates a compound that reacts with oxidized color developing agent to create or modify the hue of a dye chromophore.
In referring to blue, green and red recording dye image-forming layer units, the term “layer unit” indicates the hydrophilic colloid layer or layers that contain radiation-sensitive silver halide grains to capture exposing radiation and couplers that react upon development of the grains. The grains and couplers are usually in the same layer, but can be in adjacent layers.
The term “exposure latitude” indicates the exposure range of a characteristic curve segment over which instantaneous gamma (&Dgr;D/&Dgr;log E) is at least 25 percent of gamma, as defined above. The exposure latitude of a color element having multiple color recording units is the exposure range over which the characteristic curves of the red, green, and blue color recording units simultaneously fulfill the aforesaid definition.
The term “colored masking coupler” indicates a coupler that is initially colored and that loses its initial color during development upon reaction with oxidized color developing agent.
The term “substantially free of colored masking coupler” indicates a total coating coverage of less than 0.09 millimole/m
2
of colored masking coupler.
The term “dye image-forming coupler” indicates a coupler that reacts with oxidized color developing agent to produce a dye image.
The term “development inhibitor releasing compound” or “DIR” indicates a compound that cleaves to release a development inhibitor during color development. As defined DIR's include couplers and other compounds that utilize anchimeric and timed releasing mechanisms.
In referring to grains and emulsions containing two or more halides, the halides are named in order of ascending concentrations.
The terms “high chloride” and “high bromide” in referring to grains and emulsions indicate that chloride or bromide, respectively, is present in a concentration of greater than 50 mole percent, based on silver.
The term “equivalent circular diameter” or “ECD” is employed to indicate the diameter of a circle having the same projected area as a silver halide grain.
The term “aspect ratio” designates the ratio of grain ECD to grain thickness (t).
The term “tabular grain” indicates a grain having two parallel crystal faces which are clearly larger than any remaining crystal faces and an aspect ratio of at least 2.
The term “tabular grain emulsion” refers to an emulsion in which tabular grains account for greater than 50 percent of total grain projected area.
The terms “blue spectral sensitizing dye”, “green spectral sensitizing dye”, and “red spectral sensitizing dye” refer to a dye or combination of dyes that sensitize silver halide grains and, when adsorbed, have their peak absorption in the blue, green and red regions of the spectrum, respectively.
The term “half-peak bandwidth” in referring to a dye indicates the spectral region over which absorption exhibited by the dye is at least half its absorption at its wavelength of maximum absorption.
The term “overall half-peak bandwidth” indicates the spectral region over which a combination of spectral sensitizing dyes within a layer unit exhibits absorption that is at least half their combined maximum absorption at any single wavelength.
Research Disclosure
is published by Kenneth Mason Publications, Ltd., Dudley House, 12 North St., Emsworth, Hampshire P010 7DQ, England.
BACKGROUND OF THE INVENTION
Color photographic elements are conventionally formed with superimposed blue, green, and red recording layer units coated on a support. The blue, green, and red recording layer units contain radiation-sensitive silver halide emulsions that form a latent image in response to blue, green, and red light, respectively. Additionally, the blue recording layer unit contains a yellow dye-forming coupler, the green recording layer unit contains a magenta dye-forming coupler, and the red recording layer unit contains a cyan dye-forming coupler.
Following imagewise exposure, a negative working photographic element is processed in a color developer that contains a color developing agent that is oxidized while selectively reducing to silver the latent image bearing silver halide grains. The oxidized color developing agent then reacts with the dye-forming coupler in the vicinity of the developed grains to produce an image dye. Yellow (blue-absorbing), magenta (green-absorbing) and cyan (red-absorbing) image dyes are formed in the blue, green, and red recording layer units, respectively. Subsequently the element is bleached (i.e., developed silver is converted back to silver halide) to eliminate neutral density attributable to developed silver and then fixed (i.e., silver halide is removed) to provide stability during subsequent room light handling.
When processing is conducted as noted above, negative dye images are produced. To produce corresponding positive dye images, and hence, to produce a visual approximation of the hues of the subject photographed, white light is typically passed through the color negative image to expose a second color photographic material having blue, green, and red recording layer units as described above, usually coated on a white reflective support. The second element is commonly referred to as a color print element. Processing of the color print element as described above produces a viewable positive image that approximates that of the subject originally photographed.
A positive working color photographic element is first developed in a black-and-white developer where the exposed crystals are selectively reduced to metallic silver. The unexposed silver is then fogged and reduced by a chromogenic color developer in a subsequent step to generate cyan, magenta, and yellow image dyes. The film is further bleached and fixed as with the negative working film. The positive working film thus forms dyes in the unexposed areas and renders a positive image of the scene, directly.
A problem with the accuracy of color reproduction delayed the commercial introduction of color negative elements. In color negative imaging, two dye image-forming coupler containing elements, a camera speed image capture and storage element and an image display, i.e. print element, are sequentially exposed and processed to arrive at a viewable positive image. Since the color negative element cascades its color errors forward to the color print element, the cumulative error in the final print is unacceptably large, absent some form of color correction. Even in color reversal materials which employ just one set of image dyes, color correction for the unwanted absorption of the imperfect image dyes is required to produce acceptable image color fidelity for direct viewing.
Color corre
Buitano Lois A.
Link Steven G.
Sowinski Allan F.
Eastman Kodak Company
Le Hoa Van
Rice Edith A.
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