Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2000-08-23
2002-10-01
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S583000, C430S582000, C430S581000, C430S570000
Reexamination Certificate
active
06458524
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to a silver halide photographic light-sensitive material containing a novel compound, more specifically, the present invention relates to a silver halide photographic light-sensitive material having high sensitivity and reduced in the residual color.
BACKGROUND OF THE INVENTION
Heretofore, a great deal of efforts have been made to increase the sensitivity of silver halide photographic light-sensitive materials and reduce the persistent coloring (residual color or dye stain). Sensitizing dyes used for the spectral sensitization are known to have great effect on the capabilities of a silver halide photographic light-sensitive material. A slight difference in the structure of sensitizing dyes greatly affects the photographic capabilities such as sensitivity, fog, storage stability and residual color, however, this effect cannot be easily anticipated in advance. Therefore, many researchers have conventionally labored to synthesize a large number of sensitizing dyes and examine the photographic capabilities thereof.
The silver halide tabular grain (hereinafter referred to as a “tabular grain”) has the following photographic properties:
1) the ratio of the surface area to the volume is large and a large amount of a sensitizing dye can be adsorbed to the surface, so that higher spectral sensitization sensitivity can be obtained;
2) when an emulsion containing tabular grains is coated and dried, the grains orient in parallel to the support surface, so that the coated layer can be reduced in the thickness and good sharpness can be obtained;
3) the tabular grains oriented in parallel to the support maintain their shape and orientation after the development, so that the developed silver can exhibit high covering power; by virtue of this property, particularly in the case of an X-ray film, the coated silver amount necessary for obtaining an optical density of the same level as otherwise can be reduced;
4) the tabular grains oriented in parallel to the support reduce the light scattering, so that an image having high resolution can be obtained; and
5) the sensitivity to blue light is low, so that when the silver halide tabular grain is used in a green- or red-sensitive layer, a yellow filter can be reduced or dispensed with.
U.S. Pat. No. 4,439,520 describes a color photographic light-sensitive material improved in the sharpness, sensitivity and graininess by using a tabular grain having a thickness of less than 0.3 &mgr;m, a diameter of 0.6 &mgr;m or more and an aspect ratio of 8 or more in at least one of the green-sensitive emulsion layer and the red-sensitive emulsion layer. The aspect ratio as used herein means a ratio of the diameter of a tabular grain to the thickness. The diameter of a tabular grain as used herein means a diameter of a circle having the same area as the projected area of a grain when the emulsion is observed through a microscope or an electron microscope. The thickness as used herein is a distance between two parallel planes constituting a tabular grain.
U.S. Pat. No. 4,693,964 describes a photographic element containing silver bromide or silver iodobromide tabular grains having an average diameter of from 0.4 to 0.55 &mgr;m and an aspect ratio of 8 or more, where a tabular grain having an average diameter of 0.5 &mgr;m and a thickness of 0.04 &mgr;m is disclosed in the Examples. U.S. Pat. No. 4,672,027 describes a photographic element containing silver bromide or silver iodobromide tabular grains having an average diameter of from 0.22 to 0.55 &mgr;m and an aspect ratio of 8 or more, where a tabular grain having a thickness of 0.04 &mgr;m is disclosed in the Examples.
U.S. Pat. No. 5,250,403 describes a color photographic element containing tabular grains having a (111) main plane, an average diameter of 0.7 &mgr;m or more and an average thickness of less than 0.07 &mgr;m in a minus blue (green and/or red) layer. Tabular grains having an average thickness of less than 0.07 &mgr;m are called an “ultra-thin” tabular grain. In this patent publication, it is stated that the ultra-thin tabular grain emulsion is advantageous in view of the relationship between the sensitivity and the graininess and that this emulsion is preferably used in a color photographic element, particularly, in a minus blue recording emulsion layer, because an image having good sharpness can be obtained.
European Patent 362699 describes a tabular grain in which the ratio of the aspect ratio to the diameter of a tabular grain is larger than 0.7, where a tabular grain having a thickness of 0.04 &mgr;m is prepared in the Examples.
As such, investigations have been heretofore concentrated on the development of tabular grains having a higher aspect ratio and a smaller thickness so as to bring out the characteristic properties of the tabular grain to a higher extent. However, requirements for higher quality photographs are strong and development of techniques for achieving still higher sensitivity is keenly demanded.
As described above, the tabular grain is large in the ratio of the surface area to the volume, therefore, a large amount of a sensitizing dye can be adsorbed to the surface and thereby a higher spectral sensitization sensitivity can be obtained. Here, it is considered that by increasing the photoabsorption factor of a sensitizing dye, the efficiency in the transmission of light energy to silver halide can be increased and in turn higher spectral sensitivity can be attained.
In this way, the tabular grain is advantageous for obtaining a high spectral sensitization sensitivity but has a problem in that due to adsorption of a sensitizing dye in a large amount, the residual color after the processing increases. Thus, it is demanded to solve this problem.
From these reasons, studies are being made for a sensitizing dye having high sensitivity and reduced in the residual color.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a silver halide light-sensitive material having high sensitivity and excellent storage stability and reduced in the fogging and the residual color.
As a result of extensive investigations, the object of the present invention can be attained by the following means:
(1) a silver halide photographic light-sensitive material comprising a support having provided thereon at least one emulsion layer containing silver halide grains, which comprises at least one compound represented by the following formula (I):
wherein Z
1
and Z
2
each represents oxygen atom, sulfur atom, selenium atom, tellurium atom or a >NR group (wherein R represents an alkyl group, an aryl group or a heterocyclic group), L
1
, L
2
and L
3
each represents a methine group, n
1
represents 0, 1, 2 or 3, V
1
, V
2
, V
3
, V
4
, W
1
, W
2
, W
3
and W
4
each represents hydrogen atom or a substituent, provided that two substituents may be combined with each other to form a condensed ring on the condition that assuming the sum total of &pgr; values of the substituents V
1
to V
4
is &pgr;
v
and the sum total of &pgr; values of the substituents W
1
to W
4
is &pgr;
w
, either one of &pgr;
v
and &pgr;
w
is 0.70 or less, M represents a charge-balancing counter ion, m represents a number necessary for neutralizing the electric charge of the molecule, R
1
represents an alkyl group, an aryl group or a heterocyclic group, and R
2
represents a substituent represented by any of the following formulae:
—(L
a
)
ka
CONHSO
2
R
a
—(L
b
)
kb
SO
2
NHCOR
b
—(L
c
)
kc
CONHCOR
c
—(L
d
)
kd
SO
2
NHSO
2
R
d
—(L
e
)
ke
COOH
wherein R
a
, R
b
, R
c
and R
d
each represents an alkyl group, an aryl group, a heterocyclic group, an alkoxy group, an aryloxy group, a heterocyclyloxy group or an amino group, L
a
, L
b
, L
c
, L
d
and L
e
each represents a methylene group, and k
a
, k
b
, k
c
, k
d
and k
e
each represents an integer of 1 or more;
(2) the silver halide photographic light-sensitive material as described in (1), wherein the sum of &pgr;
v
and &pgr;
w
is 1.40 or less;
(3) the silver halide photographic light-sensitive material
Morimura Kimiyasu
Nakamura Tetsuo
Fuji Photo Film Co. , Ltd.
Letscher Geraldine
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