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Test Card F is a test card that was created by the BBC and used on television in the United Kingdom and in countries elsewhere in the world for more than four decades. Like other test cards, it was usually shown while no programmes were being broadcast. It was the first to be transmitted in colour in the UK and the first to feature a person, and has become an iconic British image regularly subject to parody. The central image on the card shows eight-year-old Carole Hersee (born 1958) playing noughts and crosses with a clown doll, Bubbles the Clown, surrounded by various greyscales and colour test signals needed to ensure a correct picture. It was first broadcast on 2 July 1967 (the day after the first colour pictures appeared to the public on television) on BBC2. The card was developed by a BBC engineer, George Hersee (1924–2001), father of the girl in the central image. It was frequently broadcast during downtime on BBC1 until that channel went fully 24 hours in November 1997, and on BBC Two until its downtime was replaced entirely by ''Pages from Ceefax'' in 1998, after which it was only seen during engineering work, and was last seen in this role in 1999. The card was also seen on ITV in the 1970s. It was also seen on Sveriges Radio in a unknown time period. 〔http://hub.tv-ark.org.uk/images/testcards/images/43_testcards/tcf_farg_tv_sweden-01.jpg〕 Test Card J, Test Card W and Test Card X, which are digitally enhanced, widescreen and high definition versions respectively, have replaced it, although they are very infrequently broadcast because the BBC now broadcasts BBC News and promo loops of programmes shown on the channel on its terrestrial channels during downtime. Testcards now only appear during the annual RBS (rebroadcast standby)〔https://www.youtube.com/watch?v=ix6uqyLvpds〕 Test Transmissions and, until 2013, during the BBC HD preview loop, which used Test Card X. ==Technical information== Virtually all the designs and patterns on the card have some significance. Along the top (see above) are 95% colour-bars in descending order of luminance—white, yellow, cyan, green, magenta, red, blue and black. There are triangles on each of the four sides of the card to check for correct overscanning of the picture. Standard greyscale and frequency response tests are found on the left and right respectively of the central picture. On the updated Test Card J, the X on the noughts-and-crosses board is an indicator for aligning the centre of the screen. The blocks of colour on the sides would cause the picture to tear horizontally if the sync circuits were not adjusted properly. The closely spaced lines in various parts of the screen allowed focus to be checked from centre to edge; mistuning would also blur the lines. All parts of the greyscale would not be distinct if contrast and brightness (both internal preset settings and user adjustments) were not set correctly. The black bar on a white background revealed ringing and signal reflections. The castellations along the top and bottom also revealed possible setup problems. A child was depicted so that wrong skin colour would be obvious and not subject to changing make-up fashions. The juxtaposed garish colours of the clown were such that a common transmission error called chrominance/luminance delay inequality would make the clown's yellow buttons turn white. Modern circuitry using large-scale integration is much less susceptible to most of these problems. Some of them are also associated with cathode ray tubes; liquid crystal displays (LCDs), that are not scanned at high speed, also help. The test card was a vital tool in its day, but has become far less important. The name of the broadcasting channel usually appeared in the space underneath the letter F—a sans-serif F denoting an original optical version of the test card. Originally, Test Card F was a photographic slide made up of two transparencies in perfect registration—one containing the colour information and the other the monochrome background. The card was converted to electronic form in 1984 when electronic storage became possible. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Test Card F」の詳細全文を読む スポンサード リンク
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