In recent years, a marked improvement has been made in image quality of silver halide multi-layered color photographic light-sensitive materials.
That is, graininess, sharpness and color reproducibility, which are integral parts of the three elements of image quality, are on substantially high levels in recent color photographic light-sensitive materials. In an ordinary color photography, for example, it seems that customers do not complain much of the quality of color prints or slidefilms they obtain.
In the color reproducibility among the three elements, however, color purity has being improved, but colors which are conventionally regarded to be hard to reproduce in photography still remain unimproved; that is, the color reproducibility has problems for solution still now. For example, purple and bluish purple which reflect a ray having a wavelength larger than 600 nm, or green-based colors such as bluish green and yellowish green, are occasionally reproduced in a color quite different from the original, disappointing users of their expectations.
A spectral sensitivity distribution and an interimage effect are decisive factors in the color reproduction.
With respect to the interimage effect, it is known to add a so-called DIR compound which forms a developing inhibitor or a precursor thereof upon reaction with an oxidation product of a color developing agent, to a silver halide multi-layered color photographic light-sensitive material. In this case, a developing inhibitor released from such a DIR compound inhibits developing of other color forming layers and thereby produces an interimage effect to improve the color reproduction.
In a color negative film, the same effect as the interimage effect can be achieved by adding a colored coupler in an amount larger than that necessary to offset useless absorptions.
However, using an excessive amount of a colored coupler causes a minimum optical density of a film to increase; this makes it difficult to form a proper judgement on the correction of color or optical density of print, thereby deterioration in color quality of print is liable to occur.
Meanwhile, these techniques contribute particularly to the enhancement of color purity in the color reproduction. A so-called diffusible DIR compound, which is frequently used in recent years and whose inhibiting group and precursor have large mobilities, contributes greatly to improvement in color purity. But, the interimage effect is difficult to be controlled in a proper direction, thereby it is liable to cause a trouble of changing a color, though it can raise the color purity (directional control of the interimage effect is described in U.S. Pat. No. 4,725,529).
With regard to the spectral sensitivity distribution, U.S. Pat. No. 3,672,898 discloses a spectral sensitivity distribution appropriate to mitigate a fluctuation in color reproduction caused by a difference in light sources at photographing. But, this is not good enough to improve the foregoing poor-reproducible colors.
As known in the photographic art, color reproductions of bluish purple and purple can be improved by shifting a spectral sensitivity distribution in a red-sensitive layer to a shorter wavelength region. This technique is described in Japanese Patent Publication Open to Public Inspection Nos. 20926/1978 and 131937/1984, but the methods described therein have a couple of shortcomings such as an insufficient color reproduction for purple of the primal object and lowering in color purity of skin color, a fatal drawback for a photographic material.
A combination of a spectral sensitivity distribution and an interimage effect is disclosed in Japanese Patent O.P.I. Publication No. 34541/1986, in which an attempt is made to improve the foregoing poor-reproducible colors and seems to produce an effect to some extent. Its typical embodiment is to exercise an interimage effect not only from a centroidal wavelength of each of blue-sensitive, green-sensitive and red-sensitive layers as performed in conventional methods, but also from wavelengths other than the centroid of each color sensitive layer.
Though this technique seems to be effective in improving reproductions of specific colors to some extent, it costs too much, because of an increased amount of silver consumption owing to necessity for providing an interimage effect producing layer besides primary blue-sensitive, green-sensitive and red-sensitive layers as well as necessity for another type of light-sensitive silver halide, in addition to a high production cost due to increase in the number of processes. Moreover, the effect is not good enough.