1939

Color Television

Peter Carl Goldmark (1906–1977)

In the 1950s, there were millions of black and white TVs in use, receiving free broadcast television channels. How did engineers bring color TV to the masses without orphaning all of those existing TV sets? This change from black and white to color TV represents a decision that engineers must frequently make: Is there value in being backward compatible with existing equipment, or is it time to abandon all of the old hardware?

In order to make a backward-compatible system for color TV, engineers would have to develop a new color signal that contains all of the necessary information for color pictures. At the same time, the signal must impersonate an older black and white signal so that it works in old B&W TVs that were built with no intention or forethought of understanding the new color signal.

This problem was solved in a remarkable way: the color information became encoded as a sine wave rippling along the normal, existing B&W signal. Older black and white TVs would ignore this new sine wave, while new color TVs could decode it.

The other problem engineers had to solve was also challenging: how to create a device that could display this new color signal. A first attempt, developed by German-Hungarian engineer Peter Goldmark for RCA in 1939, used a mechanical color wheel rotating in front of the display. This had a number of problems: it suffered from flicker and the mechanical color wheel was three times bigger than the screen itself. It felt like a kluge. Another system involved multiple CRTs (cathode ray tubes) and mirrors.

The ultimate solution was perfected and popularized by RCA in 1953—engineers developed a new form of CRT using three electron guns, three colors of phosphor in the screen, and a new shadow mask between the guns and the phosphors. With the backward-compatible color signal in place to avoid obsoleting millions of B&W sets and a new, all-electronic picture tube to display it, color TV could take off. Engineers had created an elegant system. The first national color broadcast was the Tournament of Roses Parade in 1954. The shift from analog to HDTV in 2006 echoed this original innovation.

SEE ALSO Radio Station (1920), Stadium TV Screen (1980), HDTV (1996)

Display of color television sets for sale in a department store, circa 1960s.