Field-sequential color system
One field-sequential system was developed in 1940 by Peter Goldmark for CBS, which was its sole user in commercial broadcasting.
The Federal Communications Commission adopted it on October 11, 1950, as the standard for color television in the United States.
In the late 1960s, NASA revived the Goldmark-CBS system to broadcast color video from Project Apollo Command Modules, using a camera developed by Westinghouse Electric Corporation.
It was described in the journal Nature: Baird demonstrated a modified two-color version in February 1938, using a red and blue-green filter arrangement in the transmitter; on July 27, 1939 he further demonstrated that colour scanning system in combination with a cathode ray tube with filter wheel as the receiver.
[4][5] The CBS field-sequential system was an example of a mechanical television system because it relied in part on a disc of color filters rotating at 1440 rpm inside the camera and the receiver, capturing and displaying red, green, and blue television images in sequence.
[11] CBS Television began regular, seven-day-a-week color broadcasting on June 25, 1951, in the New York City area, with a one-hour variety show hosted by Arthur Godfrey.
[12][13] In June 1951, Philco offered 11 television models that could show CBS color broadcasts in black and white.
[14] CBS purchased its own television manufacturer in April 1951 when no other company would produce color sets using the system.
[15] Production of CBS-Columbia color receivers began in September and were first offered for retail sale in October.
[18] Allen B. DuMont, owner of the DuMont Television Network, suspected that the reason CBS capitulated so easily was because of the complete lack of public interest in non-compatible color TV, and the NPA being a good excuse to cut costs and end what was a money-losing business.
[21] Meanwhile, RCA continued working on and improving its NTSC compatible color television system, first demonstrated in 1949.
[23] Color broadcast studio television cameras in the 1960s, such as the RCA TK-41, were large, heavy and high in energy consumption.
They used three imaging tubes to generate red, green and blue (RGB) video signals which were combined to produce a composite color picture.
About 42 minutes into telecasting the first EVA, astronaut Alan Bean inadvertently pointed the camera at the Sun while preparing to mount it on the tripod.
The Sun's extreme brightness burned out the video pickup tube, rendering the camera useless.
When the camera was returned to Earth, it was shipped to Westinghouse, and they were able to get an image on the section of the tube that wasn't damaged.
[29] Procedures were re-written in order to prevent such damage in the future, including the addition of a lens cap to protect the tube when the camera was repositioned off the MESA.
Image quality issues appeared due to the camera's automatic gain control (AGC) having problems getting the proper exposure when the astronauts were in high contrast light situations, and caused the white spacesuits to be overexposed or "bloom".
