Color was an old idea
Color television was imagined almost as soon as black-and-white television worked. John Logie Baird demonstrated a color picture using mechanical scanning in 1928, and various inventors in the United States and Europe filed patents for color systems in the 1920s and 1930s. These early efforts used spinning discs or filters, and they were laboratory demonstrations, not broadcast services.
All of them rested on a fact about human vision: any color can be matched by mixing red, green and blue light in the right proportions. A color system therefore has to capture three versions of the scene, send the information, and reassemble it on a screen. The trouble was doing that over a single broadcast channel without breaking the existing service.
Two approaches in the United States
By the late 1940s, American television was a growing business, with a black-and-white standard that millions of sets could receive. Regulators and manufacturers had to decide how to add color. Two main proposals emerged.
- The CBS system was field-sequential. Red, green and blue images were sent one after another, and a rotating color wheel in front of the camera and the receiver kept them in step. Peter Goldmark led its development at CBS. It produced good pictures, but it was not compatible: an ordinary black-and-white set could not show the broadcast in any usable form, and sets needed a wheel or an adapter.
- The RCA system was all-electronic and dot-sequential, and it was designed to be compatible. A black-and-white receiver could display the same broadcast as a normal picture, while a color set could decode the extra color information.
The Federal Communications Commission approved the CBS standard in late 1950. In practice, it proved a poor commercial fit. The color service needed sets that could not receive existing shows, the Korean War made materials scarce, and the leading manufacturers did not support the system. The CBS color broadcasts ended within a year or so, and the question was reopened.
The compatible standard
The industry formed the second National Television System Committee (NTSC) in the early 1950s to design a color system that worked with existing sets. Engineers from several companies took part, and the result built on RCA’s research while incorporating improvements from others. The key idea was to keep the black-and-white brightness signal in its familiar form and add the color information, called chrominance, as an extra signal squeezed into the same channel. Old sets ignored it, and new sets used it.
The FCC approved the NTSC color standard in December 1953. Broadcasts began in 1954, and in the following years the network most associated with the technology, NBC, pushed color programming to encourage set sales.
On the receiving end
Early color sets were expensive, small and harder to adjust than black-and-white sets. The picture tube was a particular challenge, because color needed far more complicated cathode ray tubes than black-and-white sets did. Most color tubes of the era used a shadow mask, a metal sheet with tiny holes placed behind the screen. Three electron guns fired beams through the holes onto groups of red, green and blue phosphor dots, so each beam only struck the dots of its own color. The eye blends the dots into a continuous picture at a normal viewing distance.
Color recording on magnetic tape arrived in the late 1950s and helped networks schedule programs across time zones. Prices fell slowly. Early color sets cost many times the price of a black-and-white one, and broadcasters were reluctant to make expensive color programs for a small audience. The audience, for its part, saw little reason to buy sets when few shows used color. Over the late 1950s and early 1960s that cycle gradually broke, helped by manufacturers’ advertising, network colorcasts and improvements in tube design. By the early 1970s, color sets were reported in a majority of American homes, and in the following years black-and-white sets became the exception.
Other countries, other standards
NTSC was not adopted everywhere. Engineers in Europe saw that NTSC color was sensitive to signal errors, which could shift hues, and they worked on alternatives. Germany’s PAL system, associated with Walter Bruch, reverses part of the color signal on alternate lines so errors tend to cancel out. France’s SECAM, associated with Henri de France, transmits the color information differently. Both entered service in the late 1960s, and various countries chose among the three systems for technical, commercial and political reasons, which is why video equipment from different regions was often incompatible. Japan began color broadcasts in 1960 using the NTSC system, while Britain launched color on its BBC2 channel in 1967 with PAL.
Why compatibility won
The color story is a case study in how standards are chosen. The first approved system was arguably elegant, but it required viewers to give up the sets they already owned. The compatible system was more complex to build, but it let the existing audience keep watching. Backward compatibility has since been a recurring theme in broadcasting, including the later move to digital television, where the question was how to handle viewers whose old sets would not work.
Color changed what programs looked like and how they were made. Studios needed far more electric lighting, makeup and costumes had to be reconsidered, and some genres, such as nature programs, sports and variety shows, gained an obvious advantage. By the time the first generation of color sets had worn out, color was simply what television looked like.