Abstract: The novel method for producing a coded marking on a CRT faceplate panel having an exterior and an interior surface with a viewing area surrounded by a periphery and having a luminescent screen with a plurality of different light-emitting phosphors separated by light-absorbing material includes the steps of: depositing a suitable photoresist on the interior surface of the panel to form a layer that extends across the viewing area and onto the periphery; illuminating areas of the photoresist on both the viewing area and the periphery with actinic radiation to selectively change the solubility of the photoresist; developing the photoresist to remove the more soluble areas, thereby exposing underlying portions of the interior surface of the panel while leaving retained areas of less soluble photoresist. The retained areas of the photoresist and the exposed portions of the interior surface of the panel are then overcoated with a light-absorbing material which is dried to form a coating.