Photosensitive composition and planographic printing plate base using same

摘要

The present invention provides a photosensitive composition for an infrared laser used for direct plate making, which has high sensitivity and good developing latitude and storage stability, and provides a planographic printing plate in which this composition is used. The positive-type photosensitive composition of the present invention has (a) a macromolecular compound having alkali-soluble groups and (b) a compound that has a phthalocyanine skeleton and has in its molecule at least one group which can form a bond by interaction with an alkali-soluble group in the macromolecular compound (a).