1. A screen assembly for displaying an image including monochrome and color image portions, comprising: a transparent plate; a transparent conductive anode on a first surface of the plate; a first light emissive layer covering a first portion of the anode, the first light emissive layer including a monochrome cathodoluminescent material; and a second light emissive layer covering a second portion of the anode the second light emissive layer including a color cathodoluminescent material operable to selectively emit light in a first wavelength range in response to a first excitation signal and to emit light in a second wavelength range in response to a second excitation signal.