Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2003-02-03
2004-08-17
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S517000, C430S519000, C430S520000, C430S521000, C430S522000, C430S508000
Reexamination Certificate
active
06777175
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a silver halide photographic material for direct observation and an ink-jet recording sheet which exhibits a high lightness and an optimal white background together with improved viewing light source dependency of the white background and also excellent sharpness.
BACKGROUND OF THE INVENTION
A silver halide photographic material for direct observation (hereinafter, also referred to as a photographic material) is composed of a silver halide emulsion layer on a support provided with a subbing layer.
RC paper is known as a typical support used for a silver halide photographic material for direct observation. In addition, there are a transparent oriented polyethylene terephthalate base, a white oriented polyethylene terephthalate base, an oriented polypropylene base and a cellulose triacetate base.
RC paper is comprised of a paper base of which both sides are laminated with polymer layers such as polyolefin, typically polyethylene layers (hereinafter, also referred to as PE layers). A PE layer provides waterproofing to RC paper and also is useful to provide a smooth surface for a light-sensitive silver halide emulsion layer formed after coating a silver halide emulsion layer.
As a PE layer on RC paper used for photographic material, usually employed is titanium dioxide and other white pigments added into the PE layer of a silver halide emulsion layer coating side (hereinafter, also referred to as a surface PE layer). Since the white background after photographic processing is preferred by consumers to be a slightly bluish white, a coloring agent and a fluorescent brightening agent may appropriately be added into the surface PE layer.
Meanwhile, in cases when PE is laminated on a paper base, a melt extrusion method after high temperature treatment of the PE is commonly employed. Since the temperature of high temperature treatment of PE is usually more than 290° C., additives to PE such as white pigments, coloring agents and fluorescent brightening agents have to be extremely stable chemically and also in color. Thus, the closest attention is paid to selecting additives, which usually are quite expensive.
Even when the most appropriate selection is made, some defects such as aggregation of a coloring agent or bleed-out of a fluorescent brightening agent may occur in the rare occasions, resulting in spots on the image after processing of the photographic material. Special high-temperature filtration may be required to minimize the undesirable aggregation, and requiring tremendous attention and undesired expenses.
Consequently, a photographic material obtaining the most appropriate white background after photographic processing is desired, in which the expensive RC paper containing a coloring agent and a fluorescent brightening agent in a surface PE layer is not employed.
Further, blending of PE, white pigments and coloring agents is usually accomplished before extrusion of a PE layer onto a paper base. Consequently, in cases when changes of color are required to adjust to some color change of RC paper or successive image forming layers, it is basically impossible to change the color.
For the above-mentioned problems of a white background adjusting methods of RC paper, methods to adjust a white background by addition of a waterproof dye or pigment into the emulsion layer are proposed in JP-A 2-842 and JP-A 2001-75231 (hereinafter, the term JP-A means Japanese Patent Application Publication). In these cases, adjusting to a slightly bluish white background is accompanied by very large decrease in lightness, and even then the preferred white background cannot be obtained.
Further, a support other than RC paper, for example, a white polyethylene terephthalate base containing voids usually does not contain a coloring agent and exhibits a different white background from that of RC paper containing a coloring agent in the surface PE layer, and the white background of the photographic material after photographic processing differs as a result.
As mentioned above, a photographic material capable of exhibiting a stable white background is required even when PC paper or the image forming layer varies, or the support is a different type.
Meanwhile, light sources vary where printed images of photographic materials are observed. Shades of color vary depending on light sources such as sunlight through a window, tungsten light and fluorescent light, and differences in vision of white background also vary with light sources. In the past, light source dependency of white background was rarely considered, however, lessening of light source dependency of white background is now important when excellent printed images are required.
In image quality of photographic materials, demand for higher quality images is increasing due to popularization of color print paper. In this situation, studies of color reproduction, tone reproduction, improved sharpness and glossiness of color print paper have widely been achieved.
Irradiation and halation are generally known as factors of print image sharpness. The former is caused by scattering of incident light by silver halide particles and oil particles of couplers dispersed in gelatin layers, and the degree depends mainly on the gelatin content, silver halide coverage and oil particle volume. The latter depends on the degree of reflection from the support, as well as depending on reflectance and refraction index of the support.
Anti-irradiation has been enhanced by addition of a water-soluble dye. The improvements are described in JP-A Nos. 50-145125, 52-20830, 50-111641, 61-148448, 61-151650, 62-275562 and 62-283336.
Anti-halation is known to provide an anti-halation layer. Examples of these improvements are described in JP-A Nos. 55-33172, 59-193447, 59-151650 and 62-33448.
However, these methods have caused a tremendous decrease of sensitivity, even with improvement of sharpness. With these means only, it was a difficult to enhance sharpness while maintaining practically sufficient sensitivity.
Color printed images are comprised of cyan images, magenta images and yellow images, and sharpness of yellow images is the most superior and that of cyan images is the most inferior. This result is caused by that a yellow image layer is usually in the nearest image layer to a support and a cyan image layer is in the farthest image layer from the support.
Meanwhile, sharpness of 3 color images is preferably on par with each other as much as possible in terms of print quality. It is desired that 3 color images exhibit high sharpness, however relative sharpness of the 3 color images is approximate.
Further, the degree of the white background is an important property, as it is also in an ink-jet recording sheet, and adjustments have been accomplished. A resin coated paper support is employed for high quality ink-jet recording sheet, and a white pigment is added into the resin of a support to increase whiteness and opacity. The particles containing fine voids are often added in high volume in an ink absorbing layer to absorb ink. Thus, further addition of an additive to adjust tint of white background tends to cause surface defects, resulting in the necessity of using a highly effective additive as a consequence.
SUMMARY OF THE INVENTION
The inventors' study resulted in achieving an ink-jet recording sheet exhibiting high lightness and a most appropriate white background. Also, an ink-jet recording sheet exhibiting improved viewing light source dependency of white background was obtained.
The first object of this invention is to provide a silver halide photographic material for direct observation which is low in cost, exhibits high lightness and a most appropriate white background. The second object of this invention is to provide a silver halide photographic material for direct observation which exhibits excellent sharpness. The third object of this invention is to provide a silver halide photographic material for direct observation which exhibits improved viewing light source dependency of the white background. The fo
Nishijima Toyoki
Yamazaki Katsumasa
Frishauf Holtz Goodman & Chick P.C.
Konica Corporation
Letscher Geraldine
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