Abstract: A process for forming a phosphor screen of a color picture tube comprising forming a thin layer using a photosensitive composition which contains an aromatic diazonium salt as a photosensitive component and produces tackiness by exposure to actinic light on the surface of the substrate and contacting the tackified thin layer after exposure to light with phosphor particles to form each phosphor layer for emitting color is improved by using as the phosphor particles those coated with at least one surface coating material selected from the group consisting of Zn(OH).sub.2, Zn.sub.3 (PO.sub.4).sub.2 and AlPO.sub.4 in shortening the contact time between the thin layer and the phosphor particles.

Abstract: A strongly fixed patternwise coated powder layer is formed on a substrate by subjecting a thin layer of photo-sensitive composition containing an aromatic diazonium salt as a photo-sensitive component capable of becoming sticky due to the formation of a photolytic reaction product of the salt by a patternwise light exposure, thereby making the light-exposed part of the thin layer sticky, bringing the thin layer in contact with powdery grains, thereby forming a powder-containing coating layer, and contacting the powder-containing coating layer with a powdery material that reacts with the photolytic product, thereby forming a water-insoluble or slightly water-soluble solid material to fix the powdery grains to the substrate.