A field-sequential color system (FSC) is a color television system in which the primary color information is transmitted in successive images and which relies on the human vision system to fuse the successive images into a color picture. One field-sequential system was developed by Dr. Peter Goldmark for CBS, which was its sole user in commercial broadcasting. It was first demonstrated to the press on September 4, 1940,and first shown to the general public on January 12, 1950. The Federal Communications Commission adopted it on October 11, 1950 as the standard for color television in the United States, but it was later withdrawn.
Color television is a television transmission technology that includes information on the color of the picture, so the video image can be displayed in color on the television set. It is an improvement on the earliest television technology, monochrome or black and white television, in which the image is displayed in shades of gray (grayscale). Television broadcasting stations and networks in most parts of the world upgraded from black and white to color transmission in the 1970s and 1980s. The invention of color television standards is an important part of the history of television, and it is described in the technology of television article.
Peter Carl Goldmark was a Hungarian-American engineer who, during his time with Columbia Records, was instrumental in developing the long-playing microgroove 33-1/3 rpm phonograph disc, the standard for incorporating multiple or lengthy recorded works on a single disc for two generations. The LP was introduced by Columbia's Goddard Lieberson in 1948. Lieberson was later president of Columbia Records from 1956–71 and 1973–75. According to György Marx he was one of The Martians.
CBS is an American English language commercial broadcast television and radio network that is a flagship property of CBS Corporation. The company is headquartered at the CBS Building in New York City with major production facilities and operations in New York City and Los Angeles.
The use of sequential color systems for moving images predates the invention of fully electronic television. Although usually known at the time simply as "additive" rather than sequential color systems, two-color Kinemacolor, in commercial use since 1906, and its predecessor three-color format, invented by Edward Raymond Turner and patented in 1899, were both sequential natural color systems for use with motion picture film. They utilized black-and-white film and rotating color filter wheels to record the amount of each color in the scene on alternating frames of the film, so that when the frames were projected by light of similar colors at a sufficiently rapid rate, those colors blended together in the viewer's eye and produced a wider range of hues. Due to litigation by William Friese-Greene, Kinemacolor ended up in the public domain in 1915, after which several derivative sequential color processes (such as Friese-Greene's Biocolour and the original Prisma Color) were developed. Some were brought to the point of being publicly shown, but during the 1920s they could not compete with rival bipack and other subtractive color processes, which were free of color flicker and did not require special projection equipment—the final multicolored images were right there on the film as transparent coloring matter.
Additive color, or "additive mixing", is a property of a color model that predicts the appearance of colors made by coincident component lights with distinct colors, i.e. the perceived color can be predicted by summing the numeric representations of the component colors. Modern formulations of Grassmann's Laws describe the additivity in the color perception of light mixtures in terms of algebraic equations. It is important note that additive color predicts perception and not any sort of change in the photons of light themselves. These predictions are only applicable in the limited scope of color matching experiments where viewers match small patches of uniform color isolated against a grey or black background.
Kinemacolor was the first successful colour motion picture process, used commercially from 1908 to 1914. It was invented by George Albert Smith of Brighton, England in 1906. He was influenced by the work of William Norman Lascelles Davidson and, more directly, Edward Raymond Turner. It was launched by Charles Urban's Urban Trading Co. of London in 1908. From 1909 on, the process was known as Kinemacolor. It was a two-colour additive colour process, photographing and projecting a black-and-white film behind alternating red and green filters.
Edward Raymond Turner was a pioneering British inventor and cinematographer. He produced the earliest known colour motion picture film footage
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. The field rate was increased from 60 to 144 fields per second to overcome the flicker from the separate color images, resulting in 24 complete color frames per second (each of the three colors was scanned twice, double interlacing being standard for all electronic television: 2 scans × 3 colors × 24 frames per second = 144 fields per second), instead of the standard 30 frames/60 fields per second of monochrome. If the 144-field color signal were transmitted with the same detail as a 60-field monochrome signal, 2.4 times the bandwidth would be required. Therefore, to keep the signal within the standard 6-MHz bandwidth of a channel, the image's vertical resolution was reduced from 525 lines to 405. The vertical resolution was 77% of monochrome, and the horizontal resolution was 54% of monochrome.
Mechanical television or mechanical scan television is a television system that relies on a mechanical scanning device, such as a rotating disk with holes in it or a rotating mirror, to scan the scene and generate the video signal, and a similar mechanical device at the receiver to display the picture. This contrasts with modern television technology, which uses electronic scanning methods, for example electron beams in cathode ray tube (CRT) televisions, and liquid-crystal displays (LCD), to create and display the picture.
Revolutions per minute is the number of turns in one minute. It is a unit of rotational speed or the frequency of rotation around a fixed axis.
In video, a field is one of the many still images which are displayed sequentially to create the impression of motion on the screen. Two fields comprise one video frame. When the fields are displayed on a video monitor they are "interlaced" so that the content of one field will be used on all of the odd-numbered lines on the screen and the other field will be displayed on the even lines. Converting fields to a still frame image requires a process called deinterlacing, in which the missing lines are duplicated or interpolated to recreate the information that would have been contained in the discarded field. Since each field contains only half of the information of a full frame, however, deinterlaced images do not have the resolution of a full frame.
Because of these variances in resolution and frame rate from the NTSC standards for television broadcasting, field-sequential color broadcasts could not be seen on existing black and white receivers without an adapter (to see them in monochrome), or adapter-converter (to see them in color).
NTSC, named after the National Television System Committee, is the analog television color system that was used in North America from 1954 and until digital conversion, was used in most of the Americas ; Myanmar; South Korea; Taiwan; Philippines; Japan; and some Pacific island nations and territories.
CBS purchased its own television manufacturer in April 1951 when no other company would produce color sets using the system.Production of CBS-Columbia color receivers began in September; they were first offered for retail sale in October.
Field-sequential color broadcasts were suspended by CBS on October 21, 1951, ostensibly by request of the National Production Authority, which in November 1951 prohibited the manufacture of color sets for the general public during the Korean War.Only 200 color sets had been manufactured for commercial sale, and only 100 of those had shipped, when CBS suspended its color broadcasts. CBS announced in March 1953 that it had abandoned any further plans for its color system. RCA was the leading company in the television field, with a larger technical staff, more development funds, and more political success in getting the NTSC compatible color television system. RCA developed the hardware for NTSC which superseded the field-sequential system as the U.S. standard in December 1953.
The National Production Authority (NPA) was an agency of the United States government which developed and promoted the production and supply of materials and facilities necessary for defense mobilization. It was part of the Department of Commerce.
The Korean War was a war between North Korea and South Korea. The war began on 25 June 1950 when North Korea invaded South Korea following a series of clashes along the border.
According to television historian Albert Abramson, A. A. Polumordvinov invented the first field-sequential color system. Polumordvinov applied for his Russian patent 10738 in 1899. This system scanned images with two rotating cylinders.A later German patent by A. Frankenstein and Werner von Jaworski described another field-sequential system. Like the CBS System, this patent included a color wheel. Frankenstein and Jaworski applied for their patent 172376 in 1904. This patent probably inspired John Logie Baird to use a similar color wheel in his system.
John Logie Baird demonstrated a version of field-sequential color television on July 3, 1928, using a mechanical television system before his use of cathode ray tubes, and producing a vertical color image about 4 inches (10 cm) high. 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 color scanning system in combination with a cathode ray tube with filter wheel as the receiver.
For the first nine months of NTSC color in 1953–1954, CBS continued to use its field-sequential color television cameras, with the field rate and signal adapted for NTSC standards, until RCA delivered its first production model of an NTSC color camera in time for the 1954–55 season.
The Soviet Union was the only other country to experiment with a field-sequential color system. It manufactured a small number of color receivers in 1954 that used a mechanical color disc.
The field-sequential system was used in specialized applications long after it had been replaced for broadcast television. A notable user of the technology was NASA. Field-sequential color cameras were used on the Apollo lunar landing cameras which transmitted color television images from the Moon during missions from 1969 to 1972. Another system was used for the Voyager program in 1979, to take pictures and video of Jupiter. Early Space Shuttle flights (from 1981 to 1995) used cameras with interchangeable lenses. For color transmissions, a field-sequential color system was built into the lens assembly. For the NASA transmissions, the video from space was field sequential, converted by a duty cycle extension technique to component RGB color video on the ground, and thereafter converted to NTSC and other world standards like PAL and SECAM.
Modern day Digital Light Processing (DLP) projectors commonly use color wheels to generate color images, typically running at a multiple of the video frame rate.
Modern day LCD displays implement FSC by using several colors of LED backlight, by cycling the backlights, and gain several advantages such as brighter colors, darker blacks, and lower cost.These displays are used in LCD Camera viewfinders and other industrial applications.
Analog television or analogue television is the original television technology that uses analog signals to transmit video and audio. In an analog television broadcast, the brightness, colors and sound are represented by rapid variations of either the amplitude, frequency or phase of the signal.
Chrominance is the signal used in video systems to convey the color information of the picture, separately from the accompanying luma signal. Chrominance is usually represented as two color-difference components: U = B′ − Y′ (blue − luma) and V = R′ − Y′ (red − luma). Each of these difference components may have scale factors and offsets applied to it, as specified by the applicable video standard.
The RGB color model is an additive color model in which red, green and blue light are added together in various ways to reproduce a broad array of colors. The name of the model comes from the initials of the three additive primary colors, red, green, and blue.
Video is an electronic medium for the recording, copying, playback, broadcasting, and display of moving visual media. Video was first developed for mechanical television systems, which were quickly replaced by cathode ray tube (CRT) systems which were later replaced by flat panel displays of several types.
Interlaced video is a technique for doubling the perceived frame rate of a video display without consuming extra bandwidth. The interlaced signal contains two fields of a video frame captured at two different times. This enhances motion perception to the viewer, and reduces flicker by taking advantage of the phi phenomenon.
The shadow mask is one of the two technologies used in the manufacture of cathode ray tube (CRT) televisions and computer displays which produce clear, focused color images. The other approach is the aperture grille, better known by its trade name, Trinitron. All early color televisions and the majority of CRT computer monitors used shadow mask technology. Both of these technologies are largely obsolete, having been increasingly replaced since the 1990s by the liquid-crystal display (LCD).
Color Television Inc. was an American research and development firm founded in 1947 and devoted to creating a color television system to be approved by the Federal Communications Commission as the U.S. color broadcasting standard. Its system was one of three considered in a series of FCC hearings from September 1949 to May 1950. Unlike the winning field-sequential color system by CBS, the line sequential CTI system was all-electronic with no color scanning disk, and fully compatible with existing black and white receivers. Unlike the dot sequential RCA system, it used only one scanning tube in the camera and one picture tube in the receiver. CTI's camera used three lenses, behind which were mounted red, blue, and green color filters that produced three images side by side on a single scanning tube. At the receiver, the three images were received on three separate areas of a picture tube, each area treated with different phosphorescent compounds that glowed in red, blue, or green. Superimposing lenses were used to merge the separate images into a single color image on a rear projection screen in the television set.
The penetron, short for penetration tube, is a type of limited-color television used in some military applications. Unlike a conventional color television, the penetron produces a limited color gamut, typically two colors and their combination. Penetrons, and other military-only cathode ray tubes (CRTs), have been replaced by LCDs in modern designs.
The 405-line monochrome analogue television broadcasting system was the first fully electronic television system to be used in regular broadcasting.
The invention of the television was the work of many individuals in the late 19th century and early 20th century. Individuals and corporations competed in various parts of the world to deliver a device that superseded previous technology. Many were compelled to capitalize on the invention and make profit, while some wanted to change the world through visual and audio communication technology.
The Apollo program used several television cameras in its space missions in the late 1960s and 1970s; some of these Apollo TV cameras were also used on the later Skylab and Apollo–Soyuz Test Project missions. These cameras varied in design, with image quality improving significantly with each successive model. Two companies made these various camera systems: RCA and Westinghouse. Originally, these slow-scan television (SSTV) cameras, running at 10 frames per second (fps), produced only black-and-white pictures and first flew on the Apollo 7 mission in October 1968. A color camera – using a field-sequential color system – flew on the Apollo 10 mission in May 1969, and every mission after that. The Color Camera ran at the North American standard 30 fps. The cameras all used image pickup tubes that were initially fragile, as one was irreparably damaged during the live broadcast of the Apollo 12 mission's first moonwalk. Starting with the Apollo 15 mission, a more robust, damage-resistant camera was used on the lunar surface. All of these cameras required signal processing back on Earth to make the frame rate and color encoding compatible with analog broadcast television standards.
Television standards conversion is the process of changing one type of television system to another. The most common is from NTSC to PAL or the other way around. This is done so television programs in one nation may be viewed in a nation with a different standard. The video is fed through a video standards converter that changes the video to a different video system.
The Chromatron is a color television cathode ray tube design invented by Nobel prize-winner Ernest Lawrence and developed commercially by Paramount Pictures, Sony, Litton Industries and others. The Chromatron offered brighter images than conventional color television systems using a shadow mask, but a host of development problems kept it from being widely used in spite of years of development. Sony eventually abandoned it in favor of their famous Trinitron system using an aperture grille.
The Geer tube was an early single-tube color television cathode ray tube, developed by Willard Geer. The Geer tube used a pattern of small phosphor-covered three-sided pyramids on the inside of the CRT faceplate to mix separate red, green and blue signals from three electron guns. The Geer tube had a number of disadvantages, and was never used commercially due to the much better images generated by RCA's shadow mask system. Nevertheless, Geer's patent was awarded first, and RCA purchased an option on it in case their own developments didn't pan out.
The Triniscope was an early color television system developed by RCA. It used three separate video tubes with colored phosphors producing the primary colors, combining the images through dichroic mirrors onto a screen for viewing.
Telechrome was the first all-electronic single-tube color television system. It was invented by well-known Scottish television engineer, John Logie Baird, who had previously made the first public television broadcast, as well as the first color broadcast using a pre-Telechrome system.