PHOTOSENSITIVE PLANOGRAPHIC PRINTING PLATE

摘要

PURPOSE:To obtain the photosensitive planographic printing plate which has excellent exposed image visibility and developed image visibility and with which register marks are easily visible. CONSTITUTION:This photosensitive planographic printing plate contains a discoloring agent which is changed in its color tone by making interaction with at least a compd. which forms an acid and/or free group by irradiation with active rays and a photodecomposable compd. of this compd. Such printing plate has at least one minimal values between 400 to 600nm in its reflection spectra and at least one maximal values between 500 to 700nm. The min. value of at least one maximal values has <=0.50 absorbance and the max. value of at least one maximal values has >=0.85 absorbance. In addition, the ratio of the absorbance of the max. value of the maximal values to the absorbance of the min. value of the above-mentioned minimal values is <=0.5.