Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Two or more radiation-sensitive layers containing other than...
Reexamination Certificate
1999-09-03
2002-01-08
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Two or more radiation-sensitive layers containing other than...
C430S448000, C430S467000, C430S483000, C430S484000, C430S485000, C430S486000, C430S566000, C430S567000, C430S505000
Reexamination Certificate
active
06337177
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a silver halide color photographic material (also referred to as “photosensitive material” hereinafter) for recording images, and to an image formation method using the aforesaid photosensitive material.
BACKGROUND OF THE INVENTION
Silver halide-utilized photographic materials have undergone steadily increasing development in recent years and, at the present time, they can readily provide color images of high quality. In the system usually referred to as color photography, for instance, photographs are taken using a color negative film, and the image information recorded in the color negative film through development is printed optically into color photographic paper, thereby forming color prints. Recently, this process has attained highly advanced development to enable the spread of the so-called mini-laboratories, or small-sized simplified print processors installed in stores, as well as the color processing laboratories as large-scale local bases for highly efficient mass-production of color prints. As a result, everybody can be easily amused with color photographs now.
Lately, the APS system embodying a new concept, wherein the magnetic substance coated on the support of a color negative film is utilized for recording various kinds of information as magnetic record, has been introduced into the market. This system makes easy handling of films and proposes new ways of enjoying photographs. For instance, one can enjoy changing the print sizes and enables the recording of information at the time of photographing. In addition, tools for editing and processing the image information read from processed negative films by means of a simple scanner have been proposed. By utilizing such methods, high-quality image information from silver salt photographs can be readily converted into digital information, and so a wide range of applications going over the conventional ways of enjoying photographs are being popularized.
On the other hand, the so-called digital still cameras using CCD as image pickup elements are making rapid progress in their performance. With respect to the cameras intended for amateur use, it was these several years ago that the cameras loaded with CCD elements having more than several millions of pixels were beginning to appear on the market. Unlike general color photographic systems, the digital still cameras require no processes for developing exposed films, but they can directly provide digitized image information. Therefore, the taken images can be checked at once on a liquid crystal monitor, and the digital information obtained can be easily utilized for various purposes. For instance, such image information can be transferred to a printer, thereby making prints with ease, or it can be processed variously with a personal computer and easily transferred via Internet. The latest increase in density of CCD and the recent advance in performance of mass digital data dealing apparatus have enabled the printed images to acquire image quality worth viewing as photographs; as a result, discussion has opened up over the probability of substitution of those digital still cameras for conventional cameras used in photography.
Under these circumstances, it is desired to further pursue cheapness of silver halide photosensitive materials from the viewpoint of further development of the silver salt photographic system in opposition to the digital still camera system. From a structural point of view, it is impossible to produce digital still cameras at such a low price as lens-attached films.
Therefore, if it is possible to provide a picture-taking color negative which can be processed simply and rapidly and have a reduced processing load on environments while it retains a high photographic speed as a merit of silver halide photosensitive materials, an attractive system can be offered to users.
For lowering the production cost of picture-taking silver halide color photographic materials, it is desirable as a matter of course to realize the photosensitive materials having a layer structure reduced in silver coverage. However, it is difficult for conventional arts to surmount the problems of decreasing a photographic speed and rendering the gradation soft as the silver coverage is reduced. In other words, there are growing expectations for the development of photosensitive materials having low silver coverage but capable of ensuring high photographic speed and proper gradation even when they undergo simple and rapid processing which has a reduced load on environments, and the silver halide emulsions used therein are also called upon to have such properties.
One of the arts of increasing the photographic speed of a silver halide emulsion is using tabular grains. The use of tabular grains presents advantages of enhancing the efficiency in color sensitization to contribute to an increase in the photographic speed, improving the relation between photographic speed and granularity, elevating the sharpness by their specific optical properties, heightening the covering power, and so on. With respect to the relation between the thickness and the reflectance of tabular grains, as described in, e.g., A. E. Bohan & C. L. House
J. Imag. Sci. Tech.,
38, 32-35(1994), it has been suggested that the light absorption by grains cannot be increased simply by decreasing the thickness of the grains, because the region where the reflectance is elevated by the interference of light comes to appear with a decrease in grain thickness.
The arts of using the tabular grains in a commonly used liquid development system, wherein the thickness of tabular grains is selected so that the spectral reflectance of the tabular-grain emulsion layer is minimized, is disclosed in, e.g., U.S. Pat. Nos. 5,275,929 and 5,302,499. The arts of using tabular grains in the developing agent incorporated type heat development system are disclosed in, e.g., JP-A-9-274295 and JP-A-10-62932 (the term “JP-A” as used herein means an “unexamined published Japanese patent application”). However, these references have no description of using thin tabular grains at a low silver coverage.
We have now found that the enhancement of soft gradation (including the sensitivity drop of lower layers), which arises from an increase of reflectance with the decrease in the thickness of tabular grains, becomes serious when the total silver coverage exceeds 5 g/m
2
, and the sensitivity drop and the soft gradation enhancement can be reduced even under a low silver coverage condition when the developing agent-incorporated photosensitive material having a total silver coverage of at most 5 g/m
2
, particularly the material further having heat development suitability, contains an emulsion comprising tabular silver halide grains having an average thickness of 0.20 &mgr;m or below as at least one emulsion comprised in the highest-speed emulsion layer of the light-sensitive layers having the same color sensitivity. In other words, we are the first persons to find that the use of a thin tabular-grain emulsion in a developing agent-incorporated photosensitive material having a low silver coverage, particularly when the photosensitive material is a heat-developable silver halide color photographic material for picture-taking use, is effective in preventing the sensitivity drop and soft gradation enhancement from occurring with the decrease in silver coverage.
SUMMARY OF THE INVENTION
Therefore, one object of the invention is to provide a color photographic material enabling simple and rapid image formation with a reduced load on environments.
Another object of the invention is to provide a color photographic material having a reduced silver coverage but capable of achieving high speed and appropriate gradation even when it undergoes simple and rapid processing.
As a result of our intensive study, it has been found that, even when the photosensitive material has a total silver coverage of at most 5 g/m
2
, both sensitivity drop and enhancement of soft gradation can be unexpectedly reduced to a great exte
Fuji Photo Film Co. , Ltd.
Letscher Geraldine
LandOfFree
Silver halide color photographic material and image... does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Silver halide color photographic material and image..., we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Silver halide color photographic material and image... will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-2865033