Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-07-13
2003-10-14
Baxter, Janet (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S567000
Reexamination Certificate
active
06632596
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to silver halide color photographic light sensitive materials capable of invariably producing prints having stable high quality, irrespective of the conventional analog exposure system or the recent digital exposure system, and a planar exposure system or a scanning exposure system, and in particular to silver halide color photographic print materials exhibiting minimized variation in contrast over a wide exposure time range of 10
−6
to 100 sec and superior latent image stability over the period after being exposed and before being processed.
BACKGROUND OF THE INVENTION
Silver halide photographic light sensitive materials (hereinafter, also referred to as photographic light sensitive materials or simply as photographic materials) exhibiting superior advantages to other photosensitive materials, such as high sensitivity and superior tone reproduction, are broadly used today.
However, along with the recent tendency of rapid digitization, there have been increased opportunities of conducting a digital system exposure using laser lights for photographic materials. With such a trend, suitability for high intensity exposure for an ultra-short period of mili-seconds to nano-second levels and suitability for scanning exposure are desired for color paper as photographic materials used for color prints. Further, in view of the rapid advancement of non-silver output media such as an ink-jet recording system is strongly required development of photographic materials exhibiting superiorities in image quality, cost and mass-productivity.
Silver chloride emulsions or high chloride silver halide emulsions have been employed for color paper as a means for achieving rapid access. It is well known that a technique of doping iridium compounds is effective for improving the reciprocity law failure characteristic which is an inherent problem of silver halide emulsions. However, it has been proved that when shortening the processing time and an improvement of the reciprocity law failure characteristic are accomplished by such a technique, variation in photographic performance during the period of exposure to processing, i.e., deterioration in so-called latent image stability resulted. Various attempts for improving such a problem have been made so far but a means for overcoming sufficiently such a problem has not yet found out. Specifically in recent problems involved in suitability for exposure to high intensity light for a ultra-short period of time through a digital exposure system, sufficiently acceptable performance in practical use was not achieved only by commonly known techniques for improving reciprocity law failure.
As prior art regarding these, U.S. Pat. No. 4,933,272 discloses a technique in which the use of a face-centered cubic lattice silver halide emulsion occluding a complex comprising a metal selected from groups 5 to 10 inclusive of the periodical table of elements and a nitrosyl or thionitrosyl ligand resulted in an improvement in reciprocity law failure, leading to high contrast images. Similar techniques are disclosed in JP-A Nos. 6-235992, 6-235993, 6-235994 and 6-242539, thereby leading to high contrast characteristics (hereinafter, the term, JP-A refers to an unexamined and published Japanese Patent Application). Further, JP-A Nos. 8-179454, 8-211529 and 8-211530 also disclose a similar technique, in which iridium compounds are used in combination with the foregoing techniques, thereby increasing a contrast in the toe portion and leading to high contrast images. Similarly, JP-A 10-307357 teaches that a compound forming a deep permanent electron trap is allowed to be included in the interior of silver halide grains, leading to a high contrast silver halide emulsion.
However such techniques are mainly intended to achieve high contrast and nothing is taught therein with respect to improvements in reciprocity law failure characteristics over a wide range of exposure and latent image stability, as intended in the present invention.
Other technique applicable to the digital exposure system include, for example, chemical and spectral sensitization suited for formation of a bromide-localized phase, as described in U.S. Pat. No. 4,601,513 and the use of silver iodochloride emulsions, as described in European Patent Nos. 750,222 and 772,079.
Studies have been made by the inventors of this application, with intention of providing a low-priced print outputting material achieving invariably stable photographic performance, irrespective of an exposure system such as an analog system or digital system, exhibiting superior latent image stability and it was proved that the foregoing prior art was insufficient to achieve such an objective. It was unexpected from the prior art and surprising that the foregoing objective was achieved in the embodiments of the present invention.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a silver halide color photographic light sensitive material capable of invariably producing prints of stable high quality, irrespective of the conventional analog exposure system or the recent digital exposure system as well as a planar exposure system or a scanning exposure system. In particular, it is to provide a silver halide emulsion exhibiting minimal variation in contrast over a wide exposure time range of 10
−6
to 100 sec and superior latent image stability over the period after being exposed and before being processed, and a silver halide photographic material containing the emulsion and an image forming process by scanning exposure of the photographic material.
As a result of the inventors' extensive study aimed to overcome the foregoing problems, the above-described objects are achieved through the following constitution:
a silver halide emulsion comprising silver halide grains having a chloride content of not less than 90 mol %, wherein the silver halide grains each contain an iridium compound (A) and a compound (B) which functions as an electron trap stronger than that of the compound (A) when the compound (B) is doped under the same condition as compound (A); the silver halide grains satisfying the following requirement:
10
<X<
1000 and 0
<Y≦X
wherein X represents an average number of molecules of the iridium compound (A) contained per grain and Y represents an average number of molecules of the compound (B) contained per grain; and
A silver halide emulsion comprising silver halide grains, wherein the silver halide grains each have a chloride content of not less than 90 mol % and are internally doped with an iridium compound (A), a compound (B) forming a stronger electron trap than said iridium compound (A) and a compound (C) comprising a metal selected from group 8 of the periodical table of elements except for iridium and at least an CN ligand; the silver halide grains satisfying the following requirement:
100
<Z/Y<
10000
wherein Y represents an average number of molecules of said compound (B) contained per grain and Z represents an average number of molecules of said compound (C) contained per grain.
Suitable means for solving the problems and embodiments of the invention preferably achieve the objects of the invention.
DETAILED DESCRIPTION OF THE INVENTION
One feature of the silver halide emulsion relating to the invention (also denoted as an emulsion according to the invention or the inventive emulsion) is a silver halide emulsion having a relatively high chloride content, a so-called high chloride-containing silver halide emulsion. Specifically, a high chloride silver halide grain emulsion having a chloride content of 90 mol % or more is preferred, which may be any of halide compositions, including silver chloride, silver bromochloride, silver iodobromochloride and silver iodochloride. Of these preferred is silver bromchloride or silver iodochloride having a chloride content of not less than 97 mol %. A silver halide emulsion having a chloride content of 98 to 99.9 mol % is more preferred in terms of rapid processability an
Baxter Janet
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
Walke Amanda C.
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