Black and white print advertisement for Sylvania Electric Products, Inc. The advertisement features images of a picture tube, a solid-state electroluminescent display, and a larger image of several picture tube screens artistically displayed in an arc. The text describes rare-earth phosphors testing and development at the company.

In 1954, the first picture tubes, also known as cathode ray tubes (CRTs), were produced by the RCA Corporation, but it wasn't until 1963 that the first rectangular color CRTs were offered to the public. Phosphors used in CRTs were classified according to color, persistence, luminance, intended use, chemical composition, safety, and other properties. In 1965, brighter rare earth phosphors began replacing dimmer, cadmium-containing red and green phosphors. Eventually, blue phosphors were replaced as well. Examples of rare earth phosphors are yttrium oxide for red or yttrium silicide for blue.