Abstract: In forming a fluorescent screen for a color picture tube having triads of phosphor materials of the three primary colors arranged in a predetermined pattern on the inner surface of a panel, a photosensitive film which exhibits stickiness when exposed to a threshold amount of light is formed on the inner surface of the panel. Locations of the photosensitive film where the three color phosphor materials respectively occupy are exposed to light from a light source through a shadow mask mounted to the panel. The amount of exposure light for a first color phosphor material is the threshold or above and that for second and third phosphor materials is below the threshold. After completion of the light exposures for the first to third color phosphor materials through the shadow mask, the shadow mask is dismounted from the panel and the first color phosphor material is deposited onto the photosensitive film.

Abstract: A filter layer for intercepting the undesired light passage is interleaved between the panel of a color cathode ray tube and the photosensitive phosphor coating, the photosensitive phosphor coating is backwardly exposed through the filter layer to actinic radiation of the back exposure to form phosphor elements with good adhesion and position.