It is known to form a photographic image with an extremely high contrast using a silver halide photographic light-sensitive material. As silver halide light-sensitive materials adapted for such purpose, lith type silver halide light-sensitive materials are known. In phtographic plate-making processes, continuous change in density of an original is usually converted to change in area of halftone dot by exposing through a contact screen. Therefore, tone reproducibility of the image is determined by tone of halftone dot image, or halftone gradation. In order to obtain high-quality prints with good tone reproducibility, it is necessary to realize a halftone gradation having a wide tone reproducibility of from minimum halftone dot area to maximum halftone dot area. In addition, long halftone gradation is useful for preventing deterioration of halftone gradation reproducibility due to optical blurring in the case of enlarging or reducing in size a halftone dot image using a camera. Another important quality of lith type silver halide light-sensitive materials as well as the tone reproducibility of halftone dot image is the quality of individual halftone dots constituting the halftone dot image. Points for evaluating halftone dot quality include sharpness, inking properties, and uniformity of halftone dots. In general, acceleration of development of a lith type light-sensitive material tends to shorten halftone gradation, although halftone dot quality is improved.
Techniques for lengthening the halftone gradation of lith type silver halide photographic light-sensitive material described hereinbefore, such as addition of a development-inhibiting compound to an emulsion layer, generally deteriorate halftone dot quality, and hence it is difficult to lengthen halftone dot gradation without deterioration of halftone dot quality. With respect to halftone dot quality, a problem exists with ordinary lith type silver halide photographic light-sensitive materials. That is, when halftone dot quality of the maximum dot is suitable, development of the minimum dots is somewhat inhibited, whereas when halftone dot quality of the minimum dots is suitable, development of the maximum dots becomes excessive. Thus, it is extremely difficult to obtain suitable halftone dot quality for both the minimum dots and the maximum dots.
USPTO Backgrounds
USPTO Backgrounds