To provide a modifying liquid for a nonpicture part of lithographic printing plate which uses a silver complex salt diffusion transfer method so as to solve such problems that, although a correcting liquid to correct a silver image part of lithographic printing plate which uses a silver complex salt diffusion transfer method (DTR method) has come into practical use, a modifying liquid for a nonpicture part is definitely unknown and that the nonpicture part of lithographic printing plate which uses the DTR method is often damaged in the plate making process or during handled after the plate making process.
The modifying liquid contains inorganic fine particles having ≤0.1 μm average particle size, and preferably inorganic fine particles of ≤0.05 μm size. As for the inorganic fine particles, for example, colloidal silica, silica obtained by a vapor phase method, alumina sol or the like can be used. The content of the inorganic fine particles is 30 to 300 g per 11 of the modifying liquid, and preferably 50 to 250 g. Further, the modifying liquid preferably contains phenylphocphonic acid or its derivative.
SHIMONODAN SATOSHI
AKAIWA IZUMI
