Early Color Television
Baird Mechanical Color System (1928-1940)
John Logie Baird demonstrated a color TV system, the first one that actually worked, in 1928. Baird used a Nipkow disk, with the disk divided into three sections, each with its own spiral system of holes, with each section covered by a red, green, or blue filter. As the disk spun, it scanned a red image, followed by a green image, then a blue image, generating all three components of a full color image with each turn of the disk.
A similar disk in the receiver decoded the three signals, and displayed them on a small screen. The screen consisted of a grid of cells containing either neon for red light, helium for blue light, or mercury for green light. The images were bright and vivid, but the screen was tiny and the frame rates low. Here is an article in the Journal of the Royal Society of Arts from 1934 (courtesy of Brian Ake).
Radio News, October 1928
Courtesy of American Radio History
Washington Post, July 7, 1928
In 1938, Baird designed a mechanical system for theaters. It used a carbon arc lamp as the light source, and a mirror drum. Here is a 1997 article in Electronics World about the system.
Television & Short Wave World, March 1938
Courtesy of Kevin Edwards