Desensitising compsn - for lithographic plates contg hydrophilic colloid,dialdehyde and molybdate ions

摘要

The colloid is gum arabic, the dialdehyde is glyoxal and the molybdate ions are provided by sodium molybdate. The compsn is acidified to pH 2-5 with phosphoric acid. The compsn. also contains a wetting agent pref. a water soluble polyethylene glycol with a mol.wt. of 6000-20000 and glycerol. Used for desensitising lithographic plates. The treated plates allow repeated stops during printing with a minimum of staining or inking faults.