Radiation imagery chemistry: process – composition – or product th – Radiation sensitive product – Silver compound sensitizer containing
Reexamination Certificate
2001-09-14
2003-07-15
Letscher, Geraldine (Department: 1752)
Radiation imagery chemistry: process, composition, or product th
Radiation sensitive product
Silver compound sensitizer containing
C430S569000
Reexamination Certificate
active
06593071
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates to silver halide photographic materials and silver halide photographic emulsion, and in particular to a silver halide photographic material and silver halide photographic emulsion which are improved in sensitivity reduction and deterioration in image quality, due to radiation.
BACKGROUND OF THE INVENTION
Recently, desire for optimal performance of silver halide color photographic materials has become severe, and photographic characteristics such as sensitivity, fog and graininess and storage stability are demanded at higher levels. As a result of recent popularization of compact zoom cameras and lens-fitted cameras used as a single use camera, photographing instruments and materials are carried to various locations and expected to be placed under severe conditions (such as being allowed to stand inside cars in the summer season). Accordingly, in photographing materials, higher performance is required for storage stability before exposure or over the period of from exposure to being processed. However, conventional techniques are insufficient for such requirements and further improvements are desired.
Along with recent trends of speed enhancement of photographic materials, there are concerns about problems such as increased fogging, speed-reduction and deterioration in graininess of silver halide photographic materials, caused by baggage checks using X-rays in air terminals. Increased fogging, speed reduction and graininess deterioration during storage, specifically caused by trace amounts of radiation in environments has become problematic. It is known that these influences caused by radiation can be reduced to some extent by reduction of silver coverage per unit area of photographic material. However, reduced silver coverage also results in a lowering of sensitivity and deterioration of image quality and there are limits to be compatible with prevention of deterioration in performance caused by radiation.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide a silver halide photographic material and a silver halide photographic emulsion, exhibiting improvements in lowering in sensitivity and deterioration in image quality.
The foregoing object of the invention can be accomplished by the following constitution:
a silver halide emulsion comprising silver halide grains, wherein at least 50% of total grain projected area is accounted for by tabular grains having dislocation lines in the fringe portion, the tabular grains each comprising an internal region and a shell (V1);
the internal region comprising a silver halide phase (V3) having a maximum average iodide content, a silver halide phase (V6) located inside the silver halide phase (V3) and having an average iodide content of A6 mol %, and a silver halide phase (V7) located outside the silver halide phase (V3) and having an average iodide content of A7 mol %, and the following requirement being met:
0≦A6/A7≦1.0;
the shell (V1) accounting for 10 to 50% by volume of the grain and having an average iodide content of 4 to 20 mol %, the shell (V1) comprising one or more sub-shells including an outermost sub-shell (V2), the outermost sub-shell (V2) accounting for 1 to 15% by volume of the grain and having an average iodide content of 0 to 3 mol %; and
a silver halide color photographic light-sensitive material comprising a support having thereon a blue-sensitive layer, a green-sensitive layer and a red-sensitive layer, wherein the following requirement is met with respect to at least one of the yellow density, magenta density and cyan density:
10≦PG/S≦75
wherein PG represents an RMS granularity in a minimum density area and S represents a substantial fog.
DETAILED DESCRIPTION OF THE INVENTION
One aspect of the invention concerns a silver halide color photographic material comprising on a support a blue-sensitive layer, a green-sensitive layer and a red-sensitive layer, wherein the following requirement is satisfied in at least one of yellow, magenta and cyan densities:
10≦PG/S≦75
where “PG” represents a RMS granularity in the minimum density area and “P” represents a substantial fog.
With respect to at least one of the yellow, magenta and cyan densities is preferably 10≦PG/S≦65, and more preferably 10≦PG/S≦50. With respect to at least one of the magenta and cyan densities is preferably 10≦PG/S<75, and with respect to magenta density is preferably 10≦PG/S≦75.
The minimum density area refers to an unexposed area of a silver halide color photographic material relating to the invention. The RMS granularity in the minimum density area (PG) and substantial fog (S) can be determined in the following manner. Thus, when a silver halide color photographic material is processed in C-41 Process (produced by Eastman Kodak Co.), described in British Journal of Photography Annual 1988, page 196-198, the RMS granularity in the minimum density area (PG) is determined from the following formula:
Formula (A)
PG=log
10
(RMS×0.55).
Measurement is carried out by scanning a sample with a micro densitometer at a scanning aperture area of 750 &mgr;m
2
(a slit width of 5 &mgr;m and a slit length of 150 &mgr;m). A standard deviation of variation in density for the densitometry sampling number of at least 1000 is multiplied by 1000 and equally averaged out for each luminance. The thus obtained value is defined as “RMS”, which is introduced in the above-described equation. In the measurement, Wratten filter W-99 (available from Eastman Kodak Co.) is used.
Corresponding to light-sensitivity of a silver halide light-sensitive layer to be measured, for example, in the case of being blue-sensitive, green-sensitive and red-sensitive, the measurement is conducted using a blue separation filter (Wratten filter W98, available from Eastman Kodak Co.), a green separation filter (Wratten filter W99) and a red separation filter (Wratten filter W26), respectively, to determine PGb, PGg and PGr as the RMS granularity in the yellow, magenta and cyan minimum density areas.
With regard to the minimum density area, density (a) is determined when processed with the foregoing process, C-41. Similarly, density (b) is determined, provided that a color developing agent is removed from the color developer solution and the pH is adjusted to the same as the developer of C-41 using potassium hydroxide. Corresponding to light sensitivity (i.e., blue-, green- and red-sensitivity) of respective silver halide emulsion layers, the difference between densities (a) and (b) [i.e., density (a) minus density (b)] is measured through the foregoing blue-, green- and red-separation filters with a densitometer (produced by X-rite Corp.) to determine Sb, Sg and Sr as substantial fog.
One preferred embodiment of the invention is 10≦{(PGg/Sg)+(PGr/Sr)}/2≦80. In this case, 10≦{(PGg/Sg)+(PGr/Sr)}/2≦70 is more preferred and 10<{(PGg/Sg)+(PGr/Sr)}/2≦60 is still more preferred. One preferred embodiment of the invention is 10≦{(PGb/Sb)+(PGg/Sg)+(PGr/Sr)}/3≦100. In this case, 10≦{(PGb/Sb)+(PGg/Sg)+(PBr/Sr)}/3≦90 is more preferred and 10≦{(PGb/Sb)+(PGg/Sg)+(PGr/Sr)}/3≦80 is still more preferred.
The silver halide color photographic material of the invention preferably comprises at least a light-sensitive silver halide emulsion layer meeting the following requirement:
0.1≦D1/D2≦0.8
where D1 represents a mean size of developed silver in the minimum density area and D2 represents a mean size of developed silver at a density point of a color density of Dmin (i.e., minimum density) plus 0.15. In this case, 0.1≦D1/D2≦0.7 is more preferred and 0.1≦D1/D2≦0.6 is still more preferred. In the invention, the light-sensitive silver halide emulsion layer satisfying 0.1≦D1/D2≦0.8 is preferably a green-sensitive layer or red-sensitive layer, and more preferably a green-sensitive layer. In cases where the sil
Kondo Toshiya
Nagasawa Tadahiro
Uezawa Kuniaki
Konica Corporation
Letscher Geraldine
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