The Full Wiki

Color television: Wikis

Advertisements
  
  
  

Note: Many of our articles have direct quotes from sources you can cite, within the Wikipedia article! This article doesn't yet, but we're working on it! See more info or our list of citable articles.

Did you know ...


More interesting facts on Color television

Include this on your site/blog:

Encyclopedia

From Wikipedia, the free encyclopedia

Title card for NBC, promoting their broadcast "in RCA color".

Color television refers to the technology and practices associated with television's transmission of moving images in color.

In its most basic form, a color broadcast can be created by broadcasting three monochrome images, one each in the three colors of red, green and blue (RGB). When displayed in fast succession, these colors will blend together to produce a single color as seen by the viewer. One of the great technical challenges of introducing color broadcasting was the desire to reduce the high bandwidth, three times that of the existing black-and-white (B&W) standards, into something more acceptable that would not use up most of the available radio spectrum. After considerable research, the NTSC introduced a system that encoded the color information separately from the brightness, and greatly reduced the resolution of the color information in order to conserve bandwidth. The brightness image remained compatible with existing B&W television sets, at slightly reduced resolution, while color televisions could decode the extra information in the signal and produce a limited-color display. The higher resolution B&W and lower resolution color images combine in the eye to produce a seemingly high resolution color image. The NTSC standard represents a major technical achievement.

Although introduced in the U.S. in the 1950s, only a few years after black and white televisions had been standardized there, high prices and lack of broadcast material greatly slowed its acceptance in the marketplace. It was not until the late 1960s that color sets started selling in large numbers, due in some part to the introduction of GE's Porta-Color set in 1966. By the 1970s color sets had become standard, with all-color broadcasts becoming common. Color broadcasting in Europe was not standardized on the PAL format until the 1960s, and broadcasts did not start until 1967. By this point many of the technical problems in the early sets had been worked out, and the spread of color sets in Europe was fairly rapid. Most major markets in North America and Europe were all color by the mid-1970s, and by the 1980s B&W sets had been pushed into niche markets, notably low-power uses, small portable sets, or use as monitor screens in lower-cost consumer equipment and in the television industry.

The recent switch to all-digital broadcasting in the U.S. has made B&W sets largely unusable, after 50 years of compatibility with an increasingly color world.

Contents

Development

The human eye's detection system in the retina consists primarily of two types of light detectors, rod cells that capture light, dark, and shapes/figures, and the cone cells that detect color. A typical retina contains 120 million rods and 4.5 million to 6 million cones, which are divided among three groups that are sensitive to red, green and blue light. This means that the eye has far more resolution in contrast, or "luminance", than in color. However, post-processing in the optic nerve and other portions of the human visual system combine the information from the rods and cones to re-create what appears to be a high-resolution color image.

The eye has limited bandwidth to the rest of the visual system, estimated at just under 8 Mbit/s.[1] This manifests itself in a number of ways, but the most important in terms of producing moving images is the way that a series of still images displayed in quick succession will appear to be continuous smooth motion. This illusion starts to work at about 16 fps, and common motion pictures use 24 fps. Television, using power from the electrical grid, tunes its rate in order to avoid interference with the alternating current being supplied – in North America this is 60 fields a second to match the 60 Hz power, while in Europe it is 50 fps to match the 50 Hz power.

Early television

Experiments in television systems using radio broadcasts date to the 19th century, but it was not until the 20th century that advances in electronics and light detectors made development practical. A key problem was the need to convert a 2D image into a "1D" radio signal; some form of image scanning was needed to make this work. Early systems generally used a device known as a "Nipkow disk", which was a spinning disk with a series of holes punched in it that caused the spots to scan across and down the image. A single photodetector behind the disk captured the image brightness at any given spot, which was converted into a radio signal and broadcast. A similar disk was used at the receiver side, with a light source behind the disk instead of a detector.

A number of such systems were used experimentally starting as early as the 1920s, the best-known being John Logie Baird's system that was broadcast for a time in Britain. In spite of these early successes, all mechanical television systems shared a number of serious problems. Being mechanically driven, even slight differences in syncing between the signal and disk motor resulted in major image distortion. Another problem was that the image was captured in a roughly rectangular area of the disk, covering only a small portion of the face; making a larger display required increasingly unwieldy disks. Additionally, the resolution of the system was limited to the number of holes that could be punched into the disk, which was normally under 100, although there are rare examples with as many as 200 holes in them.

It was clear to a number of developers that a completely electronic scanning system would be superior, and that the scanning could be achieved in a vacuum tube via electrostatic or magnetic means. Converting this concept into a usable system took years of development and several independent advances. The two key advances were Philo Farnsworth's electronic scanning system, and Vladimir Zworykin's Iconoscope camera. The Iconoscope based on Kálmán Tihanyi's early patents, this system superseded the Farnsworth-system. With these systems, the BBC began regularly scheduled black and white television broadcasts in 1936, but these were shut down again with the start of World War II in 1939. In 1941 the first NTSC meetings produced a single standard for US broadcasts. US television broadcasts began in earnest in the immediate post-war era, and by 1950 there were 6 million televisions in the United States.[2]

All-mechanical color

The basic idea of using three monochrome images to produce a color image had been experimented with almost as soon as black and white televisions had first been built.

Among the earliest published proposals for television was one by Maurice Le Blanc in 1880 for a color system, including the first mentions in television literature of line and frame scanning, although he gave no practical details.[3] Polish inventor Jan Szczepanik patented a color television system in 1897, using a selenium photoelectric cell at the transmitter and an electromagnet controlling an oscillating mirror and a moving prism at the receiver. But his system contained no means of analyzing the spectrum of colors at the transmitting end, and could not have worked as he described it.[4] Hovannes Adamian worked on color television as early as 1907.

John Logie Baird demonstrated the world's first color transmission on July 3, 1928, using scanning discs at the transmitting and receiving ends with three spirals of apertures, each spiral with filters of a different primary color; and three light sources at the receiving end, with a commutator to alternate their illumination.[5] Baird also made the world's first color broadcast on February 4, 1938, sending a mechanically scanned 120-line image from Baird's Crystal Palace studios to a projection screen at London's Dominion Theatre.[6]

Mechanically scanned color television was demonstrated by Bell Laboratories in June 1929 using three complete systems of photoelectric cells, amplifiers, glow-tubes, and color filters, with a series of mirrors to superimpose the red, green, and blue images into one full color image.

Hybrid systems

As was the case with black and white television, an electronic means of scanning would be superior to the mechanical systems like Baird's. The obvious solution on the broadcast end would be to use three conventional Iconoscopes with colored filters in front of them to produce an RGB signal. Using three separate tubes each looking at the same scene would produce slight differences in parallax between the frames, so in practice a single lens was used with a mirror or prism system to separate the colors for the separate tubes. Each tube captured a complete frame and the signal was converted into radio in a fashion essentially identical to the existing black and white systems.

The problem with this approach was there was no simple way to re-combine them on the receiver end. If each image was sent at the same time on different frequencies, the images would have to be "stacked" somehow on the display, in real time. There is an obvious solution to this problem as well; a B&W tube is covered with a uniform layer of phosphor that glows white, but this could be replaced with a pattern of dots or stripes of colored phosphor instead. Although obvious, this solution was not practical. The electron guns used in B&W televisions had limited resolution, and if one wanted to retain the resolution of existing B&W displays, the guns would have to focus on individual dots three times smaller. This was beyond the state of the art at the time.

Instead, a number of hybrid solutions were developed that combined a conventional black and white display with a colored disk or mirror. In these systems the three colored images were sent one after each other, in either complete frames in the "field-sequential color system", or for each line in the "line-sequential" system. In both cases a colored filter was rotated in front of the display in sync with the broadcast. Since three separate images were being sent in sequence, if they used existing B&W radio signaling standards they would have an effective refresh rate of only 20 fields, or 10 frames, a second, well into the region where flicker would become visible. In order to avoid this the standards increased the frame rate considerably, making the signal incompatible with existing black and white standards.

The first electronically scanned color television demonstration was on February 5, 1940, when RCA privately showed to members of the FCC at the RCA plant in Camden, New Jersey, a television receiver producing color images by optically combining the images from two picture tubes onto a single rear-projection screen.[7]

In 1939, Hungarian engineer Peter Carl Goldmark introduced an electro-mechanical system while at CBS, which contained an Iconoscope sensor. The CBS field-sequential color system was partly mechanical, with a disc made of red, blue, and green filters spinning inside the television camera at 1,200 rpm, and a similar disc spinning in synchronization in front of the cathode ray tube inside the receiver set.[8] The system was first demonstrated to the FCC on August 29, 1940, and shown to the press on September 4.[9][10][11][12]

CBS began experimental color field tests using film as early as August 28, 1940, and live cameras by November 12.[13] NBC (owned by RCA) made its first field test of color television on February 20, 1941. CBS began daily color field tests on June 1, 1941.[14] These color systems were not compatible with existing black and white television sets, and as no color television sets were available to the public at this time, viewership of the color field tests was limited to RCA and CBS engineers and the invited press. The War Production Board halted the manufacture of television and radio equipment for civilian use from April 22, 1942 to August 20, 1945, limiting any opportunity to introduce color television to the general public.[15][16]

Advertisements

Fully electronic

On August 16, 1944, John Logie Baird gave the first demonstration of a fully electronic color picture tube. His 600-line color system used triple interlacing, using six scans to build each picture.[17][18]

RCA demonstrated to the FCC on January 29, 1947 the first all-electronic color television system, with no moving parts, to transmit live images.

FCC Color

In the immediate post-war era the FCC was inundated with requests to set up new television stations. Worrying about congestion of the limited number of channels available, they put a moratorium on all new licenses until 1948 while they considered the problem. A solution was immediately forthcoming; rapid development of radio receiver electronics during the war had opened a wide band of higher frequencies to practical use, and the FCC set aside a large section of these new UHF bands for television broadcast. At the time B&W broadcasting was still in its infancy in the U.S., and the FCC started to look at ways of using this newly available bandwidth for color broadcasts. Since no existing television would be able to tune in these stations, they were free to pick an incompatible system and allow the older VHF channels to die off over time.

The FCC called for technical demonstrations of color systems in 1948, and the "Joint Technical Advisory Committee" (JTAC) was formed to study them. CBS displayed improved versions of their original design, now using a single 6 MHz channel (like the existing B&W signals) at 144 fields per second and 405 lines of resolution. Color Television Inc. demonstrated their line-sequential system, while Philco demonstrated a dot-sequential system based on their "Apple" tube technology. Of the entrants, the CBS system was by far the best developed, and won head-to-head testing every time.

While the meetings were taking place it was widely known within the industry that RCA was working on a dot-sequential system that was compatible with existing B&W broadcasts, but declined to demonstrate it during the first series of meetings. Just before the JTAC presented their findings, on 25 August 1949 RCA broke its silence and introduced their system as well. The JTAC still recommended the CBS system, and after the resolution of an ensuing RCA lawsuit, color broadcasts using the CBS system started on June 25, 1951. By this point the market had changed dramatically; when color was first being considered in 1948 there were less than a million sets in the U.S., but by 1951 there were well over 10 million. The idea that the VHF band could be allowed to "die" was no longer practical.

During its campaign for FCC approval, CBS gave the first demonstrations of color television to the general public, showing an hour of color programs daily Mondays through Saturdays, beginning January 12, 1950, and running for the remainder of the month, over WOIC in Washington, D.C., where they could be viewed on eight 16-inch color receivers in a public building.[19] Due to high public demand, the broadcasts were resumed February 13–21, with several evening programs added.[20] CBS initiated a limited schedule of color broadcasts from its New York station WCBS-TV Mondays to Saturdays beginning November 14, 1950, making ten color receivers available for the viewing public.[21][22] All were broadcast using the single color camera that CBS owned.[23] The New York broadcasts were extended by coaxial cable to Philadelphia's WCAU-TV beginning December 13,[24] and to Chicago on January 10,[25][26] making them the first network color broadcasts.

After a series of hearings beginning in September 1949, the FCC found the RCA and CTI systems fraught with technical problems, inaccurate color reproduction, and expensive equipment, and so formally approved the CBS system as the U.S. color broadcasting standard on October 11, 1950. An unsuccessful lawsuit by RCA delayed the first commercially-sponsored network broadcast in color until June 25, 1951, when a musical variety special titled simply Premiere was shown over a network of five east coast CBS affiliates.[27] Viewership was again extremely limited: the program could not be seen on black and white sets, and Variety estimated that only thirty prototype color receivers were available in the New York area.[28] Regular color broadcasts began that same week with the daytime series The World Is Yours and Modern Homemakers.

While the CBS color broadcasting schedule gradually expanded to twelve hours per week (but never into prime time),[29] and the color network expanded to eleven affiliates as far west as Chicago,[30] its commercial success was doomed by the lack of color receivers necessary to watch the programs, the refusal of television manufacturers to create adapter mechanisms for their existing black and white sets,[31] and the unwillingness of advertisers to sponsor broadcasts seen by almost no one. CBS had bought a television manufacturer in April,[32] and in September 1951, production began on the only CBS-Columbia color television model, with the first color sets reaching retail stores on September 28.[33][34] But it was too little, too late. Only 200 sets had been shipped, and only 100 sold, when CBS discontinued its color television system on October 20, 1951, ostensibly by request of the National Production Authority for the duration of the Korean conflict, and bought back all the CBS color sets it could to prevent lawsuits by disappointed customers.[35][36] RCA chairman David Sarnoff later charged that the NPA's order had come "out of a situation artificially created by one company to solve its own perplexing problems" because CBS had been unsuccessful in its color venture.[37]

Compatible color

While the FCC was holding its JTAC meetings, development was taking place on a number of systems allowing true simultaneous color broadcasts, "dot-sequential color systems". Unlike the hybrid systems, dot-sequential televisions used a signal very similar to existing B&W broadcasts, with the intensity of every dot on the screen being sent in succession.

In 1938 Georges Valensi demonstrated an encoding scheme that would allow color broadcasts to be encoded so they could be picked up on existing B&W sets as well. In his system the output of the three camera tubes were re-combined to produce a single "luminance" value that was very similar to a B&W signal and could be broadcast on the existing VHF frequencies. The color information was encoded in a separate "chrominance" signal, consisting of two separate signals, the original blue signal minus the luminance (B'–Y'), and red-luma (R'–Y'). These signals could then be broadcast separately on a different frequency; a B&W set would tune in only the luminance signal on the VHF band, while color televisions would tune in both the luminance and chrominance on two different frequencies, and apply the reverse transforms to retrieve the original RGB signal. The downside to this approach is that it required a major boost in bandwidth use, something the FCC was interested in avoiding.

RCA used Valensi's concept as the basis of all of their developments, believing it to be the only proper solution to the broadcast problem. However, their early sets using mirrors and other projection systems all suffered from image and color quality problems, and were easily bested by CBS's hybrid system. But solutions to these problems were in the pipeline, and RCA in particular was investing massive sums (later estimated at $100 million) to develop a usable dot-sequential tube. They were beaten to the punch by the Geer tube, which used three B&W tubes aimed at different faces of colored pyramids to produce a color image. All-electronic systems included the Chromatron, Penetron and "Apple" tube that were being developed by various companies. While investigating all of these, RCA's teams quickly started focusing on the shadow mask system.

In July 1938 the shadow mask color television was patented by Werner Flechsig (1900-1970) in Germany, and was demonstrated at the International radio exhibition Berlin in 1939. Most CRT color televisions used today are based on this technology. His solution to the problem of focusing the electron guns on the tiny colored dots was one of brute-force; a metal sheet with holes punched in it allowed the beams to reach the screen only when they were properly aligned over the dots. Three separate guns were aimed at the holes from slightly different angles and when their beams passed through the holes this slight angled caused them to separate again and hit the individual spots a short distance away on the back of the screen. The downside to this approach was that the mask cut off the vast majority of the beam energy, allowing it to hit the screen only 15% of the time, which required a massive increase in beam power to produce acceptable image brightness.

In spite of these problems in both the broadcast and display systems, RCA pressed ahead with development and were ready for a second assault on the standards by 1950.

Second NTSC

The possibility of a compatible color broadcast system was so compelling that the NTSC decided to re-form, and held a second series of meetings starting in January 1950. Having only recently selected the CBS system, the FCC heavily opposed the NTSC's efforts. One of the FCC Commissioners, R. F. Jones, went so far as to assert that the engineers testifying in favor of a compatible system were "in a conspiracy against the public interest".

Unlike the FCC approach where a standard was simply selected from the existing candidates, the NTSC would produce a board that was considerably more pro-active in development. When RCA submitted their system they used two 6 MHz

Starting before CBS color even got on the air, the U.S. television industry, represented by the National Television System Committee, worked in 1950–1953 to develop a color system that was compatible with existing black and white sets and would pass FCC quality standards, with RCA developing the hardware elements. RCA first made publicly announced field tests of the dot sequential color system over its New York station WNBT in July 1951.[38] When CBS testified before Congress in March 1953 that it had no further plans for its own color system,[39] the National Production Authority dropped its ban on the manufacture of color television receivers,[40] and the path was open for the NTSC to submit its petition for FCC approval in July 1953, which was granted on December 17.[41] The first publicly announced network demonstration of a program using the NTSC "compatible color" system was an episode of NBC's Kukla, Fran and Ollie on August 30, 1953, although it was viewable in color only at the network's headquarters.[42] The first network broadcast to go out over the air in NTSC color was a performance of the opera Carmen on October 31, 1953.[43][44]

Adoption

North America

United States

NBC made the first coast-to-coast color broadcast when it telecast the Tournament of Roses Parade on January 1, 1954, with public demonstrations given across the United States on prototype color receivers by manufacturers RCA, General Electric, Philco, Raytheon, Hallicrafters, Hoffman, Pacific Mercury and others.[45] A color model from Westinghouse ($1,295, or $10.5 thousand in today's[46] dollars) became available in the New York area on February 28 and is generally agreed to be the first production receiver using NTSC color offered to the public;[47] a less expensive color model from RCA reached dealers in April.[48] Television's first prime time network color series was The Marriage, a situation comedy broadcast live by NBC in the summer of 1954.[49] NBC's anthology series Ford Theatre became the first network color filmed series that October.[50]

Early color telecasts could be preserved only on the black and white kinescope process introduced in 1947. It wasn't until September 1956 that NBC began using color film to time-delay and preserve some of its live color telecasts.[51] Ampex introduced a color videotape recorder in 1958, which NBC used to tape An Evening With Fred Astaire, the oldest surviving network color videotape.

Several syndicated shows had episodes filmed in color during the 1950s, including The Cisco Kid, The Lone Ranger, My Friend Flicka, and Adventures of Superman. The first two were carried by some stations equipped for color telecasts well before NBC began its regular weekly color dramas in 1959, beginning with the Western series Bonanza.

NBC was at the forefront of color programming because its parent company RCA manufactured the most successful line of color sets in the 1950s, and by 1959 RCA was the only remaining major manufacturer of color sets.[52] CBS and ABC, which were not affiliated with set manufacturers, and were not eager to promote their competitor's product, dragged their feet into color.[53][54] CBS ceased all regular color programming between 1960 and 1965 (including at least one of their shows, The Lucy Show, which was filmed in color, beginning in 1963, but continued to be telcast in black and white through the end of the 1964-65 season), while ABC delayed its first color series until 1962.[55] The DuMont network, although it did have a television-manufacturing parent company, was in financial decline by 1954 and was dissolved two years later.[56] Thus the relatively small amount of network color programming, combined with the high cost of color television sets, meant that as late as 1964 only 3.1 percent of television households in the U.S. had a color set. NBC provided the catalyst for rapid color expansion by announcing that its prime time schedule for fall 1965 would be almost entirely in color.[57] All three broadcast networks were airing full color prime time schedules by the 1966–67 broadcast season, and ABC aired its last new black and white daytime programming in December 1967.[58] But the number of color television sets sold in the U.S. did not exceed black and white sales until 1972, which was also the first year that more than fifty percent of television households in the U.S. had a color set.[59] This was also the year that "in color" notices before color television programs ended[citation needed], due to the rise in color television set sales, and color programming having become the norm.

Cuba

Cuba in 1958 became the second country in the world to introduce color television broadcasting, with Havana's Channel 12 using the NTSC standard and RCA equipment. But the color transmissions ended when broadcasting stations were seized in the Cuban Revolution in 1959, and did not return until 1975, using equipment acquired from Japan's NEC Corporation, and SECAM equipment from the Soviet Union, adapted for the NTSC standard.[60]

Mexico

In Mexico, Guillermo González Camarena invented an early color television transmission system. He received patents for color television systems in 1942 (U.S. Patent 2,296,019), 1960 and 1962. The 1942 patent (filed in Mexico on August 19, 1940) was for a synchronized color filter wheel adapter for monochrome television, similar to the field sequential color receiver demonstrated by Baird in England in July 1939[61] and by CBS in the United States in August 1940.

On August 31, 1946 González Camarena sent his first color transmission from his lab in the offices of The Mexican League of Radio Experiments at Lucerna St. #1, in Mexico City. The video signal was transmitted at a frequency of 115 MHz. and the audio in the 40 metre band. He obtained authorization to make the first publicly announced color broadcast in Mexico, on February 8, 1963, of the program Paraíso Infantil on Mexico City's XHGC-TV, using the NTSC system which had by now been adopted as the standard for color programming.

A field-sequential color television system similar to his Tricolor system was used in NASA's Voyager mission in 1979, to take pictures and video of Jupiter.[62]

Canada

Color television became available in Canada soon after regular color broadcasting began in the neighboring United States. Canadian stations began their own color broadcasts on July 1, 1966, both in English and in French.

Europe

European color television was developed somewhat later and was hindered by a continuing division (and nationalistic bias) on technical standards. Having decided to adopt a higher-definition 625-line system for monochrome transmissions, with a lower frame rate but with a higher overall bandwidth, Europeans could not directly adopt the U.S. color standard. This was widely perceived as inadequate anyway because of its hue error problems, which became particularly acute with the introduction of videotape recorders in the late 1950s. There was also less urgency, since there were fewer commercial motivations, European television broadcasters being predominantly state-owned at the time.

As a consequence, although work on various color encoding systems started already in the 1950s, with the first SECAM patent being registered in 1956, many years had passed when the first broadcasts actually started in 1967. Unsatisfied with the performance of NTSC and of initial SECAM implementations, the Germans unveiled PAL (phase alternating line) in 1963, technically similar to NTSC but borrowing some ideas from SECAM. The French continued with SECAM, notably involving Russians in the development.

The first full-specification PAL receivers ("PAL-D") relied on a precision ultrasonic glass delay line, which in the early days was estimated would make up about a third of the cost of the receiver. PAL stood for Phase Alternated Line. It was basically a 625-line version of NTSC, with phase inversion of alternate numbered scan lines. Therefore, for example, a HUE or TINT (phase) error on line 22 would be offset be an opposite HUE or TINT error on line 23. The two phase errors would cancel each other in the optical presentation interpreted by the human eye. The TINT control required by NTSC was therefore obviated. Other color encoding systems had already been proposed which would overcome the tint problems of NTSC using such a delay line, but PAL was unique in that an economy receiver (known as "PAL-S" for "simple PAL") could also be built without using a delay line, with a performance no worse than, and in most cases better than an equivalent NTSC model.

SECAM did not require such precision for its delay line, and could use much cheaper magnetostrictive metal types. Ironically, by the time PAL broadcasts commenced in 1967, advances in glassmaking techniques had dropped the cost of precision PAL delay lines so much that hardly any simple-PAL receivers were built commercially, and virtually all SECAM receivers used the same type of delay line as PAL receivers. By the end of the 20th century, glass delay lines had been completely replaced by all-electronic equivalents.

The first regular color broadcasts in Europe were by the United Kingdom's BBC2 beginning on July 1, 1967 (PAL). West Germany's first broadcast occurred in August (PAL), followed by France in October (SECAM). Norway, Sweden, Finland, Belgium, the Netherlands, Austria, East Germany, Czechoslovakia and Hungary all started regular color broadcasts before the end of 1969.

The PAL system spread through most of Western Europe and on into the territories of the old British, Portuguese, Belgian, Dutch, Austro-Hungarian, Ottoman and Chinese Empires.

In Italy there were debates to adopt a national color television system, the ISA, developed by Indesit, but that idea was scrapped. As a result, Italy was one of the last European countries to officially adopt the PAL system in 1977, after long technical experimentation.[63]

France, Luxembourg and most of the Eastern Bloc along with their overseas territories opted for SECAM. SECAM was a popular choice in countries with a lot of hilly terrain, and technologically backward countries with a very large installed base of monochrome equipment, since the greater ruggedness of the SECAM signal could cope much better with poorly maintained equipment. However for many countries the decision was more down to politics than technical merit.

The only real drawback of SECAM is that, unlike PAL or NTSC, post-production of an encoded SECAM is not really possible without a severe drop in quality.

The first regular color broadcasts in SECAM were started on October 1, 1967, on France's Second Channel (ORTF 2e chaîne). In France and the UK color broadcasts were made on UHF frequencies, the VHF band being used for legacy black and white, 405 lines in UK or 819 lines in France, till the beginning of the eighties. Countries elsewhere that were already broadcasting 625-line monochrome on VHF and UHF, simply transmitted color programmes on the same channels.

It should be noted that some British television programmes, particularly those made by or for ITC Entertainment, were shot on color film before the introduction of color television to the UK, for the purpose of sales to US networks. The first British show to be made in color was the drama series The Adventures of Sir Lancelot (1956-57), which was initially made in black and white but later shot in color for sale to the NBC network in the United States. Other British color television programmes include Stingray (1964-1965), which was the first British TV show to filmed entirely in color, Thunderbirds (1965-1966) and Captain Scarlet and the Mysterons (1967-1968). However, other UK series, such as Doctor Who (1963-89; 2005-present) didn't begin color production until later, with the first color Doctor Who episodes not airing until 1970.

Asia and the Pacific

Alaska and Hawaii, the last two U.S. states to join the union, both started using color television in the mid-1960s, Hawaii in September 1965, and Alaska exactly a year later. In Japan, NHK introduced color television, using a variation of the NTSC system (called NTSC-J), on September 10, 1960. The Philippines (1966) and Taiwan (1969) also adopted the NTSC system. Other countries in the region instead used the PAL system, starting with Australia (1967), and then Hong Kong (1970), China (1971), New Zealand (1973), Singapore (1974), Thailand (1975) and Indonesia (1978), with India not introducing it until 1982. South Korea did not introduce color (using NTSC) until 1980, although it was already manufacturing color television sets for export.

Middle East

Nearly all of the countries in the Middle East use PAL, except for Azerbaijan, Armenia, and Georgia which are part of the Commonwealth of Independent States. The first country in the Middle East to introduce color television was Iraq in 1967. Saudi Arabia, the United Arab Emirates, Kuwait, Bahrain, and Qatar followed in the mid-1970s, but Israel, Lebanon and Cyprus continued to broadcast in black and white until the early 1980s.

Africa

The first color television service in Africa was introduced on the Tanzanian island of Zanzibar, in 1973, using PAL. At the time, South Africa did not have a television service at all, owing to opposition from the apartheid regime, but in 1976, one was finally launched. Nigeria adopted PAL for color transmissions in 1974 in the then Benue Plateau state in the north central region of the country, but countries such as Ghana and Zimbabwe continued with black and white until 1984.

South America

In contrast to most other countries in the Americas, which had adopted NTSC, Brazil began broadcasting in color in PAL-M. Its first transmission was on February 19, 1972. However Chile and Ecuador were the first South American countries to receive color TV, using NTSC. It transmission was on October 1972 and November 5, 1973 respectively. Some countries in South America, including Argentina, Colombia, Uruguay, Peru and Venezuela, continued to broadcast in black and white until the late 1970s.

Color standards

There are three main standards in use around the world, PAL (Phase Alternating Line), NTSC (National Television System Committee) and SECAM (Séquentiel Couleur à Mémoire—Sequential Color with Memory).

The system used in North America is NTSC. Western Europe, Australia, and Eastern South America use PAL. Eastern Europe used SECAM, but switched to PAL after the change of the political regimes there. France still uses SECAM. Generally, a device (such as a television) can only read or display video encoded to a standard which the device is designed to support; otherwise, the source must be converted (such as when European programs are broadcast in North America or vice versa). Because a tint control is unnecessary in PAL, NTSC has jokingly been said to stand for Never Twice the Same Color.[64]

This table illustrates the differences:

NTSC M PAL B,G,H PAL I PAL N PAL M SECAM B,G,H SECAM D,K,K',L
Lines/Fields 525/60 625/50 625/50 625/50 525/60 625/50 625/50
Horizontal Frequency 15.734 kHz 15.625 kHz 15.625 kHz 15.625 kHz 15.750 kHz 15.625 kHz 15.625 kHz
Vertical Frequency 60 Hz 50 Hz 50 Hz 50 Hz 60 Hz 50 Hz 50 Hz
Color Subcarrier Frequency 3.579545 MHz 4.43361875 MHz 4.43361875 MHz 3.582056 MHz 3.575611 MHz
Video Bandwidth 4.2 MHz 5.0 MHz 5.5 MHz 4.2 MHz 4.2 MHz 5.0 MHz 6.0 MHz
Sound Carrier 4.5 MHz 5.5 MHz 5.9996 MHz 4.5 MHz 4.5 MHz 5.5 MHz 6.5 MHz

References

  1. ^ Michael Reilly, "Calculating the speed of sight", New Scientist, 28 July 2006
  2. ^ "Television", The World Book Encyclopedia 2003: 119
  3. ^ M. Le Blanc, "Etude sur la transmission électrique des impressions lumineuses", La Lumière Electrique, vol. 11, 1 December 1880, p. 477–481.
  4. ^ R. W. Burns, Television: An International History of the Formative Years, IET, 1998, p. 98. ISBN 0852969147.
  5. ^ John Logie Baird, Television Apparatus and the Like, U.S. patent, filed in U.K. in 1928.
  6. ^ Baird Television: Crystal Palace Television Studios. Previous color television demonstrations in the U.K. and U.S. had been via closed circuit.
  7. ^ Kenyon Kilbon, Pioneering in Electronics: A Short History of the Origins and Growth of RCA Laboratories, Radio Corporation of America, 1919 to 1964, Chapter Nine — Television: Monochrome to Color, 1964. V.K. Zworykin with Frederick Olessi, Iconoscope: An Autobiography of Vladimir Zworykin, Chapter 10 — Television Becomes a Reality, 1945-1954, 1971. "The system used two color filters in combination with photocells and a flying spot scanner for pickup." Alfred V. Roman, The Historical Development of Color Television Systems, doctoral dissertation, New York University, 1967, p. 49.
  8. ^ Peter C. Goldmark, assignor to Columbia Broadcasting System, "Color Television", U.S. Patent 2,480,571, filed Sept. 7, 1940.
  9. ^ Current Broadcasting 1940
  10. ^ "Color Television Success in Test", The New York Times, August 30, 1940, p. 21.
  11. ^ "Color Television Achieves Realism", The New York Times, Sept. 5, 1940, p. 18.
  12. ^ "New Television System Transmits Images in Full Color", Popular Science, December 1940, p. 120.
  13. ^ "Color Television Success in Test," New York Times, Aug. 30, 1940, p. 21. "CBS Demonstrates Full Color Television," Wall Street Journal, Sept. 5, 1940, p. 1. "Television Hearing Set," New York Times, Nov. 13, 1940, p. 26.
  14. ^ Ed Reitan, RCA-NBC Color Firsts in Television (commented).
  15. ^ "Making of Radios and Phonographs to End April 22," New York Times, March 8, 1942, p. 1. "Radio Production Curbs Cover All Combinations," Wall Street Journal, June 3, 1942, p. 4. "WPB Cancels 210 Controls; Radios, Trucks in Full Output," New York Times, August 21, 1945, p. 1.
  16. ^ Bob Cooper, "Television: The Technology That Changed Our Lives", Early Television Foundation.
  17. ^ Albert Abramson, The History of Television, 1942 to 2000, McFarland & Company, 2003, pp. 13-14. ISBN 0786412208
  18. ^ Baird Television: The World's First High Definition Colour Television System.
  19. ^ "Washington Chosen for First Color Showing; From Ages 4 to 90, Audience Amazed", The Washington Post, Jan. 13, 1950, p. B2.
  20. ^ "Color TV Tests To Be Resumed In Washington", The Washington Post, February 12, 1950, p. M5.
  21. ^ "CBS Color Television To Make Public Debut In N.Y. Next Week", The Wall Street Journal, November 9, 1950, p. 18.
  22. ^ CBS Announces Color Television (advertisement), New York Daily News, November 13, 1950, p. .
  23. ^ "You Can See The Blood on Color Video," The Washington Post, Jan. 15, 1950, p. L1. "Video Color Test Begins on C.B.S.," New York Times, Nov. 14, 1950, p. 44.
  24. ^ "CBS Color Preview Seen By 2,000 in Philadelphia", The Wall Street Journal, December 16, 1950, p. 10.
  25. ^ "CBS to Display Color Video in City Next Week", Chicago Tribune, Jan. 6, 1951, television and radio section, p. C4.
  26. ^ "Preview of CBS Color TV Wins City's Acclaim", Chicago Tribune, Jan. 10, 1951, p. A8.
  27. ^ "C.B.S. Color Video Presents a 'First'," New York Times, June 26, 1951, p. 31.
  28. ^ Four hundred guests watched the premiere commercial broadcast on eight color receivers at a CBS studio in New York, as no color receivers were available to the general public. "C.B.S. Color Video Presents a 'First"", New York Times, June 26, 1951, p. 31. A total of about 40 color receivers were available in the five cities on the color network. The CBS affiliate in Washington had three receivers and a monitor. "First Sponsored TV in Color Praised by WTOP Audience", The Washington Post, June 26, 1951, p. 1. Most of the remainder of the prototype color receivers were given to advertisers sponsoring the color broadcasts. "Today, June 25, 1951, is a turning point in broadcasting history" (WTOP-TV advertisement), The Washington Post, June 25, 1951, p. 10.
  29. ^ Ed Reitan, "Progress of CBS Colorcasting", Programming for the CBS Color System.
  30. ^ "CBS Color System Network Affiliates", Programming for the CBS Color System.
  31. ^ "CBS Color System Makes Television Set Makers See Red", Wall Street Journal, October 17, 1950, p. 1. Three exceptions among the major television manufacturers were Philco, which offered 11 models that could show CBS color broadcasts in black and white; and Westinghouse and Admiral, which offered adapters to receive color broadcasts in black and white. "Philco Offers 11 TV Sets To Receive CBS Color TV in Black and White", Wall Street Journal, June 4, 1951, p. 9. "Westinghouse to Sell Adapter for CBS Color TV Signals", Wall Street Journal, August 7, 1951, p. 18.
  32. ^ "Hytron's Deal With CBS Seen TV Color Aid", The Washington Post, April 12, 1951, p. 15.
  33. ^ "CBS Subsidiary Starts Mass Production of Color Television Sets," Wall Street Journal, Sep 13, 1951, p. 18.
  34. ^ "Para-TV Color Sets To Go On Sale Soon", Billboard, October 6, 1951, p. 6.
  35. ^ "Text of Note to CBS Asking Color Set Halt", Billboard, Oct. 27, 1951, p. 11.
  36. ^ "Color TV Shelved As a Defense Step," New York Times, Oct 20, 1951, p. 1. "Action of Defense Mobilizer in Postponing Color TV Poses Many Question for the Industry," New York Times, Oct. 22, 1951, p. 23. Ed Reitan, CBS Field Sequential Color System, 1997.
  37. ^ "NPA Refs Verbal Slugfest in M-90 Revamp Study; Color TV Future Dim", Billboard, Feb. 16, 1952, p. 5.
  38. ^ "RCA to Test Color TV System On Three Shows Daily Beginning Today", The Wall Street Journal, July 9, 1951, p. 3.
  39. ^ "CBS Says Confusion Now Bars Color TV," Washington Post, March 26, 1953, p. 39.
  40. ^ "N.P.A. Decides to End Restrictions on Output Of Color TV Sets", The Wall Street Journal, March 21, 1953, p. 1.
  41. ^ "F.C.C. Rules Color TV Can Go on Air at Once," New York Times, Dec. 19, 1953, p. 1.
  42. ^ "NBC Launches First Publicly-Announced Color Television Show," Wall Street Journal, August 31, 1953, p. 4.
  43. ^ Ed Reitan, RCA-NBC Firsts in Television.
  44. ^ Jack Gould, "Television in Review: Further Thoughts on Color", The New York Times, Nov. 2, 1953, p. 34. Prototype color TV sets had been distributed to RCA and NBC executives, advertisers, TV retailers, and journalists in the New York City area.
  45. ^ "Television in Review: N.B.C. Color," New York Times, Jan. 4, 1954, p. 28. Two days earlier Admiral demonstrated to their distributors the prototype of Admiral's first color television set planned for consumer sale using the NTSC standards, priced at $1,175 ($9.51 thousand in today's dollars). It is not known when the later commercial version of this receiver was first sold. Production was extremely limited, and no advertisements for it were published in New York or Washington newspapers. "First Admiral Color TV," New York Times, Dec 31, 1953, p. 22. "Admiral's First Color TV Set," Wall Street Journal, Dec. 31, 1953, p. 5. "TV Firm Moves to Golden Triangle", The Pittsburgh Press, Feb. 23, 1954, p. 9.
  46. ^ Consumer Price Index (estimate) 1800–2008. Federal Reserve Bank of Minneapolis. Retrieved March 8, 2010.
  47. ^ Westinghouse display ad, New York Times, Feb. 28, 1954, p. 57. Only 30 sets were sold in its first month. "Color TV Reduced by Westinghouse," April 2, 1954, p. 36.
  48. ^ RCA's manufacture of color sets started March 25, 1954, and 5,000 Model CT-100's were produced. Initially $1,000, its price was cut to $495 in August 1954 ($4.01 thousand in today's dollars). "R.C.A. Halves Cost of Color TV Sets," New York Times, Aug. 10, 1954, p. 21.
  49. ^ "News of TV and Radio," New York Times, June 20, 1954, p. X11.
  50. ^ After 15 episodes in color, Ford reduced costs by making only every third episode in color. "Ford Cuts Back on Color Film", Billboard, Oct. 30, 1954, p. 6. The syndicated Cisco Kid had been filmed in color since 1949 in anticipation of color broadcasting. "'Cisco Kid' for TV Via Pact With Ziv", Billboard, Sept. 24, 1949, p. 47. "Ziv to Shoot All New Series in B & W and Color Versions", Billboard, April 4, 1953, p. 10.
  51. ^ Albert Abramson, The History of Television, 1942 to 2000, McFarland, 2003, p. 74. ISBN 9780786412204.
  52. ^ RCA made about 95 percent of the color television sets sold in the U.S. in 1960. Peter Bart, "Advertising: Color TV Set Output Spurred," New York Times, July 31, 1961, p. 27.
  53. ^ "ABC to Go Tint at First Sponsor Nibble", Billboard, Sept. 4, 1954, p. 8.
  54. ^ "Chasing the Rainbow," Time, June 30, 1958.
  55. ^ The Flintstones, The Jetsons, and Beany and Cecil. "A.B.C.-TV To Start Color Programs," New York Times, April 1, 1962, p. 84. "More Color," New York Times, Sept. 23, 1962, p. 145. Ed Reitan, RCA-NBC Firsts in Television. Jack Gould, "Tinted TV Shows Its Colors," New York Times, Nov. 29, 1964, p. X17.
  56. ^ Clarke Ingram, The DuMont Television Network, Chapter Seven: Finale. The small amount of color programming that DuMont broadcast in 1954–1955 (mostly its show Sunday Supplement) was all from color films.
  57. ^ The exceptions being I Dream of Jeannie and Convoy.
  58. ^ The game show Everybody's Talking. The last black and white series on network television was MisteRogers' Neighborhood on the non-commercial NET in August 1968.
  59. ^ Television Facts and Statistics — 1939 to 2000, Television History — The First 75 Years.
  60. ^ Roberto Diaz-Martin, "The Recent History of Satellite Communications in Cuba", Selection of a Color Standard, in Beyond the Ionosphere: Fifty Years of Satellite Communication (NASA SP-4217, 1997).
  61. ^ "Color Television: Baird Experimental System Described", Wireless World, August 17, 1939, p. 145.
  62. ^ ^ *Enrique Krauze - Guillermo Gonzalez-Camarena Jr. "50 años de la televisión mexicana" (50th anniversary of Mexican T.V.) - Year 1999 Mexican T.V. Documentary produced by Editorial Clío & Televisa, broadcasted on 2000)
  63. ^ The adoption of color television in Italy (Italian).
  64. ^ Jain, Anal K., Fundamentals of Digital Image Processing, Upper Saddle River NJ: Prentice Hall, 1989, p. 82.

Advertisements






Got something to say? Make a comment.
Your name
Your email address
Message