| 摘要 |
PURPOSE:To obtain a photosensitive material showing a remarkable hue change at the exposed part, forming a visible image of high contrast and giving a superior imge by development under a yellow safelight lamp after exposure by adding a condensate of naphthoquinone diazido-sulfone and an azo compound. CONSTITUTION:A coating material is prepared by dissolving a compound represented by formula I or II (where each of Ar and Ar' is an optionally substituted benzene ring) in ethylcellosolve or the like together with alkali-soluble phenol-formaldehyde resin or a condensate of an o-quinone diazide compound. By applying the coating material to an Al plate and drying it a photosensitive layer is formed to obtain a lithographic original plate. When the plate is exposed through an original, the exposed part lone discolors remarkably to obtain a latent image which can be seen under a safelight lamp, and the exposed part is thoroughly removed by dissolution in an alkaline developer. Thus, a fine image is obtd. |
