FORMATION OF PHOTOABSORPTION COAT FOR COLOR PICTURE TUBE

PURPOSE:To prevent a pin hole form occurring in a coat, by separating and removing the nonradiative photoabsorbing material coated on a photoresist coat and on top of this with an aqueous solution making nitric acid and ammonium salt both a main component, at the time of forming the photoabsorbing coat. CONSTITUTION:A photoresist coat 11 constituting a pattern 14 of the photoresist formed by means of an ordinary process and nonradiative photoabsorbing mate rial 15 both separated and removed, and furthermore they are washed by water, making them into a photo-absorbing coat 16 having the required pattern. As for a remover, a mixed solution of nitric acid and inorganic ammonium or an aqueous solution added with one or more than two kinds of acid selected out of nitric acid, hydrochloric acid, hypochlorous acid, peroxisulfuric acid, boric acid, benzen sulfonic acid, sulfanilic acid and carboxylic acid is used. In this connection, as for the inorganic ammonium, any of halogenation ammo nium such as ammonium sulfate, ammonium phophate, or the like,ammonium carbonate and ammonium of boric acid will do for use.