In coating a smooth glass faceplate panel with phosphor to produce a phosphor screen for use with flat color picture tubes, a basic mask is placed onto the glass faceplate panel. Thereafter; one at a time, one coating mask for each respective color is placed over the basic mask and the phosphor belonging to the respective coating mask is deposited. The phosphor is dispersed in a reactive binder and meets with an activator sprayed on or otherwise applied to the glass faceplate panel.