PLANOGRAPHIC PRINTING PLATE

摘要

PURPOSE:To obtain excellent picture quality and extremely high printing durability without precipitation of silver in an area where exposure is impossible by using such an aluminum plate as a supporting body that has a specified or larger number of pits in a specified range of diameter per a specified area and that the average diameter of these pits is in a specified range, and by using a direct positive silver halide emulsion preliminarily fogged. CONSTITUTION:An aluminum plate roughened and anodically oxidized can be easily inspected by photographing in about 50000 magnification by using a scanning electron microscope. The number of pits having 0.03-0.30mum diameter is specified to >=500per 100mum<2>, and the average diameter of pits having 0.03-0.30mum diameter is specified to 0.05-0.20mum. As for pits except for circular shape, diameter of the pit is determined by calculating the diameter of a circulare pit of same area as that of the pit. The center depth of the pit is >=1/3 (0.01-0.10mum) of the diameter of the pit. Further a direct positive silver halide emulsion preliminarily fogged is used.