Abstract: A sign plate for an illuminated sign having a light source includes an opaque reflective layer on its face that receives light from the light source. The opaque reflective layer is broken by zones corresponding to a configuration of text, figures, and/or art design to be communicated to a viewer. The zones are covered with a light diffusion layer on the side of the light source, and the surface of the sign plate facing the viewer and opposite the light source includes a layer of reflective material in a corresponding configuration that is in general register with the configuration defined by the zones and covered by the light diffusion layer on the side of the light source.