This article offers a technical, cultural and visual genealogy of the development of screens and electronic imagery in the 20th century. While media studies have mainly focused on the technical advances of television and radar to understand these phenomena, the aim here is to draw attention to a series of North American artistic experiments dating from the interwar period. These important contributions to the investigation of the potential of electronic imagery were the fruit of a dialogue and collaboration between engineering laboratories in leading telecommunications companies and pioneering media artists. In particular, the article looks at this subject from the perspective of Thomas Wilfred’s artistic interventions using ‘Mobile Color’ and through the technical criterion of the luminous intensity of images.