Test card
Encyclopedia
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
and Australia
Australia
Australia , officially the Commonwealth of Australia, is a country in the Southern Hemisphere comprising the mainland of the Australian continent, the island of Tasmania, and numerous smaller islands in the Indian and Pacific Oceans. It is the world's sixth-largest country by total area...
, is a television
Television
Television is a telecommunication medium for transmitting and receiving moving images that can be monochrome or colored, with accompanying sound...
test signal, typically broadcast at times when the transmitter is active but no program is being broadcast (often at startup and closedown). Used since the earliest TV broadcasts, test cards were originally physical cards at which a television camera was pointed, and such cards are still often used for calibration, alignment, and matching of cameras and camcorder
Camcorder
A camcorder is an electronic device that combines a video camera and a video recorder into one unit. Equipment manufacturers do not seem to have strict guidelines for the term usage...
s. Test patterns used for calibrating or troubleshooting the downstream signal path are these days generated by test signal generator
Signal generator
Signal generators, also known variously as function generators, RF and microwave signal generators, pitch generators, arbitrary waveform generators, digital pattern generators or frequency generators are electronic devices that generate repeating or non-repeating electronic signals...
s, which do not depend on the correct configuration (and presence) of a camera. Digitally generated cards allow vendors, viewers and television stations to adjust their equipment for optimal functionality.
The test card usually has a set of line-up patterns to enable television cameras and receivers to be adjusted to show the picture correctly. (Compare with SMPTE color bars
SMPTE color bars
The SMPTE color bars are a type of television test pattern, and is most commonly used in countries where the NTSC video standard is dominant, such as those in North America. The Society of Motion Picture and Television Engineers refers to this test pattern as Engineering Guideline EG 1-1990...
.) Most modern test cards include a set of calibrated color bars which will produce a characteristic pattern of "dot landings" on a vectorscope
Vectorscope
A vectorscope is a special type of oscilloscope used in both audio and video applications. Whereas an oscilloscope or waveform monitor normally displays a plot of signal vs. time, a vectorscope displays an X-Y plot of two signals, which can reveal details about the relationship between these two...
, allowing chroma and tint to be precisely adjusted between generations of videotape or network feeds. SMPTE bars—and several other test cards—include analog black (a flat waveform at 7.5 IRE
IRE (unit)
An IRE is a unit used in the measurement of composite video signals. Its name is derived from the initials of the Institute of Radio Engineers....
, or the NTSC setup level), full white (100IRE), and a "sub-black", or "blacker-than-black" (at 0 IRE), which represents the lowest low-frequency transmission voltage permissible in NTSC broadcasts (though the negative excursions of the colourburst signal may go below 0 IRE). Between the colour bars and proper adjustment of brightness and contrast controls to the limits of perception of the first sub-black bar, an analogue receiver (or other equipment such as VTRs) can be adjusted to provide impressive fidelity. The most famous Test Card shown in the UK since 1967 and also shown in some other countries is Test Card F
Test Card F
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...
, which features a little girl (Carol Hersee) and a clown doll in a circle in the centre of the picture.
Test cards are also typically broadcast with library music (see below), a sine wave reference tone
Reference tone
A reference tone is a pure tone corresponding to a known frequency, and produced at a stable sound pressure level , usually by specialized equipment.-In media:The most common reference tone in audio engineering is a at 0dB...
, or the relayed broadcasting of a radio station
Radio station
Radio broadcasting is a one-way wireless transmission over radio waves intended to reach a wide audience. Stations can be linked in radio networks to broadcast a common radio format, either in broadcast syndication or simulcast or both...
owned by the same broadcaster. There is now a cult following for test card music.
BBC test cards
BBC test cards are identified by a letter.The most famous British
United Kingdom
The United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
test card is Test Card F
Test Card F
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...
which incorporates a colour photograph of Carole Hersee
Carole Hersee
Carole Hersee is a costume designer who is best known for appearing in the centrepiece of the iconic United Kingdom television Test Card F, which aired on BBC Television from 1967 to 1998 and was revived in 2009...
(daughter of BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
engineer George Hersee
George Hersee
George Hersee was a BBC engineer, who is most famous for his development of Test Card F. This design came about after Hersee was asked to intervene by the committee charged with the creation of technical standards for the new colour TV services.Hersee was born in Sussex, England...
) playing noughts and crosses
Tic-tac-toe
Tic-tac-toe, also called wick wack woe and noughts and crosses , is a pencil-and-paper game for two players, X and O, who take turns marking the spaces in a 3×3 grid. The X player usually goes first...
with a doll, used on the BBC
BBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
and ITV
ITV
ITV is the major commercial public service TV network in the United Kingdom. Launched in 1955 under the auspices of the Independent Television Authority to provide competition to the BBC, it is also the oldest commercial network in the UK...
from the beginning of colour broadcasts in the late 1960s . It was later updated as Test Card J
Test Card J
Test Card J is a test card, an image used to determine the quality of a broadcast television picture. It is an updated version of Test Card F, which was created by BBC engineer George Hersee, and is used to test analogue television signals...
, and for widescreen
Widescreen
Widescreen images are a variety of aspect ratios used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than the standard 1.37:1 Academy aspect ratio provided by 35mm film....
broadcasts as Test Card W
Test Card W
Test Card W is a test card, an image used to determine the quality of a broadcast television picture. It is an updated 16:9 widescreen version of Test Card F, which was created by BBC engineer George Hersee. Test Card W is similar to Test Card J, the latter being a 4:3 version...
. Test Card F
Test Card F
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...
has often been spoofed by comedian
Comedian
A comedian or comic is a person who seeks to entertain an audience, primarily by making them laugh. This might be through jokes or amusing situations, or acting a fool, as in slapstick, or employing prop comedy...
s.
Decline
Formerly a common sight, test cards are now only rarely seen outside of television studios, post-production, and distribution facilities. In particular, they are no longer intended to assist viewers in calibration of television sets. Several things have led to their demise for this purpose:- Modern microcontrollerMicrocontrollerA microcontroller is a small computer on a single integrated circuit containing a processor core, memory, and programmable input/output peripherals. Program memory in the form of NOR flash or OTP ROM is also often included on chip, as well as a typically small amount of RAM...
-controlled analogue televisions rarely if ever need adjustment, so test cards are much less important than previously. Likewise, modern cameras and camcorders seldom need adjustment for technical accuracy, though they are often adjusted to compensate for scene light levels, and for various artistic effects. - Use of digital interconnect standards, such as CCIR 601CCIR 601ITU-R Recommendation BT.601, more commonly known by the abbreviations Rec. 601 or BT.601 is a standard published in 1982 by International Telecommunication Union - Radiocommunications sector for encoding interlaced analog video signals in digital video form...
and SMPTE 292MSMPTE 292MSMPTE 292M is a standard published by SMPTE which expands upon SMPTE 259M and SMPTE 344M allowing for bit-rates of 1.485 Gbit/s, and 1.485/1.001 Gbit/s...
, which operate without the non-linearities and other issues inherent to analogue broadcasting, do not introduce colour shifts or brightness changes; thus the requirement to detect and compensate for them using this reference signal has been virtually eliminated. (Compare with the obsolescence of stroboscopeStroboscopeA stroboscope, also known as a strobe, is an instrument used to make a cyclically moving object appear to be slow-moving, or stationary. The principle is used for the study of rotating, reciprocating, oscillating or vibrating objects...
s as used to adjust the speed of record players). On the other hand, digital test signal generators do include test signals which are intended to stress the digital interface, and many sophisticated generators allow the insertion of jitterJitterJitter is the undesired deviation from true periodicity of an assumed periodic signal in electronics and telecommunications, often in relation to a reference clock source. Jitter may be observed in characteristics such as the frequency of successive pulses, the signal amplitude, or phase of...
, bit errors, and other pathological conditions that can cause a digital interface to fail. - Likewise, use of digital broadcasting standards such as the DVB and ATSC eliminates the issues introduced by modulation and demodulation of analogue signals.
- Test cards including large circles were used to confirm the linearity of the set's deflection systems. As solid-state components replaced vacuum tubeVacuum tubeIn electronics, a vacuum tube, electron tube , or thermionic valve , reduced to simply "tube" or "valve" in everyday parlance, is a device that relies on the flow of electric current through a vacuum...
s in receiver deflection circuits, linearity adjustments were less frequently required (few newer sets have user-adjustable "VERT SIZE" and "VERT LIN" controls, for example). In LCD and other deflectionless displays, the linearity is a function of the display panel's manufacturing quality; for the display to work, the tolerances will already be far tighter than human perception. - In developed countriesDeveloped countryA developed country is a country that has a high level of development according to some criteria. Which criteria, and which countries are classified as being developed, is a contentious issue...
such as the United StatesUnited StatesThe United States of America is a federal constitutional republic comprising fifty states and a federal district...
and the United KingdomUnited KingdomThe United Kingdom of Great Britain and Northern IrelandIn the United Kingdom and Dependencies, other languages have been officially recognised as legitimate autochthonous languages under the European Charter for Regional or Minority Languages...
, the financial imperatives of commercial television broadcasting mean that air-time is now typically filled with programmes and commercials (such as infomercialInfomercialInfomercials are direct response television commercials which generally include a phone number or website. There are long-form infomercials, which are typically between 15 and 30 minutes in length, and short-form infomercials, which are typically 30 seconds to 120 seconds in length. Infomercials...
s) 24 hours a day, and non-commercial broadcasters have to match this.
Test cards and other semi-static programming and their use around the world today:
- In North America, most test cards such as the famous Indian Head test cardIndian Head test cardThe Indian Head Test Pattern was a black and white television test pattern which was introduced in 1939 by RCA of Harrison, New Jersey as a part of the RCA TK-1 Monoscope...
of the 1950s and 1960s have long been relegated to history. The SMPTE color barsSMPTE color barsThe SMPTE color bars are a type of television test pattern, and is most commonly used in countries where the NTSC video standard is dominant, such as those in North America. The Society of Motion Picture and Television Engineers refers to this test pattern as Engineering Guideline EG 1-1990...
occasionally turn up, but with most North American broadcasters now following a 24-hour schedule, these too have become a rare sight. Many Canadian Broadcasting CorporationCanadian Broadcasting CorporationThe Canadian Broadcasting Corporation, commonly known as CBC and officially as CBC/Radio-Canada, is a Canadian crown corporation that serves as the national public radio and television broadcaster...
stations broadcast a modified form of the SMPTE bars (with an additional modulated ramp at the top and a CBC logo animation in place of the Q block) late at night until late 2006, when the network moved to 24-hour broadcasting. - When there are in fact no standard programmes being broadcast on the channels that do not have 24-hour programming, other, more informative features such as educational shows, e.g. the BBC Learning ZoneBBC Learning ZoneThe BBC Learning Zone is an educational strand run by the BBC as an overnight service on BBC Two. It shows programming aimed at students in Primary, Secondary and Higher Education and to adult learners...
, and teletext-type programmes such as Pages from Ceefax, ITV NightscreenITV NightscreenITV Nightscreen is a scheduled programme on the United Kingdom's ITV television network, consisting of a sequence of animated pages of information about ITV's upcoming programmes, features and special events, with an easy listening music soundtrack. The programme is used to fill the station's...
and 4-Tel On View are often broadcast, the latter type acting as the better test-card substitute as they just roll continuously. - Australian national broadcaster SBSSpecial Broadcasting ServiceThe Special Broadcasting Service is a hybrid-funded Australian public broadcasting radio and television network. The stated purpose of SBS is "to provide multilingual and multicultural radio and television services that inform, educate and entertain all Australians and, in doing so, reflect...
airs Weatherwatch, a weather map accompanied by music from albums sold by SBS and a ticker at the bottom of the screen during the early hours of the morning. - Australian community broadcaster Channel 31 in Melbourne previously aired FishcamFishcamFishcam refers to a broadcast consisting of a video camera pointed at a fishtank.- Australia :Channel 31 Melbourne, Australia, had one of the more famous and long-lasting Fishcams. The Fishcam itself was originally used as a replacement to the more common testcards, shown when the station had...
, the output of a videocamera aimed at a fish tank. - Some Philippine cable networks replace test cards with an advertisement showing the product, "a reason to go to sleep" and the time when the station will sign on.
- In Singapore, since 2004, instead of showing test cards, television channels usually air radioRadioRadio is the transmission of signals through free space by modulation of electromagnetic waves with frequencies below those of visible light. Electromagnetic radiation travels by means of oscillating electromagnetic fields that pass through the air and the vacuum of space...
channels while showing their station ID at the same time. - In Thailand, Channel 5, Channel 9 and Channel 7 broadcast the advertising program (Innovations and Quantum Television) instead, Channel 7 does not broadcast Quantum Television whole night, after Quantum Television ran for 20 minutes and it is still being closing time, it will turn to the testcard, with royal anthem before switching. Channel owned by NBN (NBN1-4 and NTV) does not broadcast advertising programs since NBN refuse from broadcasting them. NBT and TVThai does not broadcast them either, because owned by government, but when TVThai still being ITV and TITV, it broadcast.
On television networks and stations in most of the Third World
Third World
The term Third World arose during the Cold War to define countries that remained non-aligned with either capitalism and NATO , or communism and the Soviet Union...
countries, test cards are still seen because most television networks and stations in those countries do not have 24-hour programming.
Use of test patterns and test cards is still common within television production facilities. Many of these still have analogue infrastructure, and currently analogue transmissions are still found worldwide (though the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
is currently scheduled to require broadcasters to switch off the NTSC
NTSC
NTSC, named for the National Television System Committee, is the analog television system that is used in most of North America, most of South America , Burma, South Korea, Taiwan, Japan, the Philippines, and some Pacific island nations and territories .Most countries using the NTSC standard, as...
service in 2009—NTSC may still be a viable transmission means for cable television
Cable television
Cable television is a system of providing television programs to consumers via radio frequency signals transmitted to televisions through coaxial cables or digital light pulses through fixed optical fibers located on the subscriber's property, much like the over-the-air method used in traditional...
for several more years). Many artistic settings are still made by using test cards or test patterns in conjunction with devices like waveform monitor
Waveform monitor
A waveform monitor is a special type of oscilloscope used in television production applications. It is typically used to measure and display the level, or voltage, of a video signal with respect to time....
s and vectorscope
Vectorscope
A vectorscope is a special type of oscilloscope used in both audio and video applications. Whereas an oscilloscope or waveform monitor normally displays a plot of signal vs. time, a vectorscope displays an X-Y plot of two signals, which can reveal details about the relationship between these two...
s (most modern waveform monitors include vectorscope capability), and while digital transmission eliminates many of the "analogue" effects associated with analogue television, digital broadcasting has its own set of issues.
Interesting testcard features from around the world
- In ThailandThailandThailand , officially the Kingdom of Thailand , formerly known as Siam , is a country located at the centre of the Indochina peninsula and Southeast Asia. It is bordered to the north by Burma and Laos, to the east by Laos and Cambodia, to the south by the Gulf of Thailand and Malaysia, and to the...
, in January–February 2008, TV stations use their local 3-letter call signCall signIn broadcasting and radio communications, a call sign is a unique designation for a transmitting station. In North America they are used as names for broadcasting stations...
(TTV, NBN, FTV, rather than the international call sign) on the test card, instead of their channel names (TV3, TV1, TV2, TV4, etc.). - In the US, by law, all test cards must use the test tone, instead of music, or silence.
UK Testcard timeline
| Year | Notes | Channel(s) | Image | |
|---|---|---|---|---|
| 1936-1939 | The first publicly broadcast testcard. It was a simple line and circle broadcast using Baird's 30 line system, and was used to synchronise the mechanical scanning system. | BBC Television Service BBC One BBC One is the flagship television channel of the British Broadcasting Corporation in the United Kingdom. It was launched on 2 November 1936 as the BBC Television Service, and was the world's first regular television service with a high level of image resolution... |
 |
|
| 1947-1948 | The second publicly broadcast testcard. It had more specific details and was referred to as Testcard A. | BBC Television Service | ||
| 1948 | Referred to as Testcard B. Used behind the scenes but never broadcast. | None | ||
| 1948-1964 | Testcard C is released, with more specific details than Testcard B. | BBC Television Service |  |
|
| 1955 | The ITA broadcasts an unlabelled testcard on ITV. | ITV ITV ITV is the major commercial public service TV network in the United Kingdom. Launched in 1955 under the auspices of the Independent Television Authority to provide competition to the BBC, it is also the oldest commercial network in the UK... |
||
| 1955-1960 | A revised version of Testcard C is broadcast on ITV. | ITV | ||
| 1960-1964 | The ITA "Picasso Pablo Picasso Pablo Diego José Francisco de Paula Juan Nepomuceno María de los Remedios Cipriano de la Santísima Trinidad Ruiz y Picasso known as Pablo Ruiz Picasso was a Spanish expatriate painter, sculptor, printmaker, ceramicist, and stage designer, one of the greatest and most influential artists of the... " testcard is released. |
ITV |  |
|
| 1964-1985 | Testcard D is released, and is the final testcard to be released for the 405-line format. Music as well as test tones were regularly used to accompany this image on BBC1 and ITV. | BBC1 BBC One BBC One is the flagship television channel of the British Broadcasting Corporation in the United Kingdom. It was launched on 2 November 1936 as the BBC Television Service, and was the world's first regular television service with a high level of image resolution... ITV |
||
| 1964 | Testcard E is released to comply with the 625-line format. Numerous television vendors complained that the image made on screen was unattractive - its sinusoidal frequency gratings looked soft - and was therefore only used for 5 days before being replaced. | BBC1 BBC2 BBC Two BBC Two is the second television channel operated by the British Broadcasting Corporation in the United Kingdom. It covers a wide range of subject matter, but tending towards more 'highbrow' programmes than the more mainstream and popular BBC One. Like the BBC's other domestic TV and radio... ITV |
||
| 1964-1969 | Once testcard E was withdrawn, the BBC released a modified version of Testcard C with more specific details on the inside circle. | BBC1 BBC2(1964-1967) ITV |
||
| 1967-1984 | Testcard F, the most famous and used testcard, is released by the BBC to coincide with colour transmissions that started that year on 1 July on BBC2. Only limited programmes were available in colour from the start. The full output became colour on BBC2 on 2 December the same year. BBC1 and ITV started colour in 1969, and began use of this testcard, phasing out Testcard E. It features a picture of Carole Hersee Carole Hersee Carole Hersee is a costume designer who is best known for appearing in the centrepiece of the iconic United Kingdom television Test Card F, which aired on BBC Television from 1967 to 1998 and was revived in 2009... playing noughts and crosses. |
BBC1 (1969-1984) BBC2 ITV (1969-1979) |
 |
|
| 1970s | Testcard G, a variant of the Philips PM5544 Philips PM5544 The Philips PM5544 is a television pattern generator, most commonly used to provide a television station with a complex test card commonly referred to as a Philips Pattern or PTV Circle. The content and layout of the pattern was designed in the Philips TV laboratory in Copenhagen by chief engineer... test pattern, is created. It was occasionally seen on BBC1 and BBC2 during the 1970s. |
BBC1 BBC2 |
||
| 1979-1992 | The Independent Broadcasting Authority Independent Broadcasting Authority The Independent Broadcasting Authority was the regulatory body in the United Kingdom for commercial television - and commercial/independent radio broadcasts... (IBA) - Independent Television Authority Independent Television Authority The Independent Television Authority was an agency created by the Television Act 1954 to supervise the creation of "Independent Television" , the first commercial television network in the United Kingdom... (ITA) prior to 1972, introduce ETP-1 ETP-1 ETP-1 was a test card designed and used by the Independent Broadcasting Authority . After test transmissions from the IBA's Engineering Regional Operations Centre in Croydon from 1978 it was phased in on ITV over a period starting from 1979, replacing Test Card F... /Electronic Test Pattern One to replace Testcard F within the ITV regions. ETP-1 was also extensively used by Channel 4 Channel 4 Channel 4 is a British public-service television broadcaster which began working on 2 November 1982. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority , the station is now owned and operated by the Channel... and S4C S4C S4C , currently branded as S4/C, is a Welsh television channel broadcast from the capital, Cardiff. The first television channel to be aimed specifically at a Welsh-speaking audience, it is the fifth oldest British television channel .The channel - initially broadcast on... in the run up to the launch of these channels in November 1982 — using 'IBA:CH4'/'IBA:S4C' captioning instead of the 'IBA' captioning used by ITV. ETP-1 became a common sight on British television in the 1980s up until ITV started broadcasting 24 hours a day in 1988. Channel 4/S4C continued to use ETP-1 - using 'NTL:CH4'/'NTL:S4C' captioning from 1990 after the Broadcasting Act 1990 Broadcasting Act 1990 The Broadcasting Act 1990 is a law of the British parliament, often regarded by both its supporters and its critics as a quintessential example of Thatcherism. The aim of the Act was to reform the entire structure of British broadcasting; British television, in particular, had earlier been... saw the privatisation of the IBA's transmitter network and sale to National Transcommunications Limited Arqiva Arqiva is a telecommunications company which provides infrastructure and broadcast transmission facilities in the United Kingdom and Republic of Ireland. The present company, with headquarters located at Crawley Court in the village of Crawley, Hampshire, was formed by National Grid Wireless... (NTL). However ETP-1 disappeared in 1992 when Channel 4 simply broadcast its teletext service 4-Tel on View whilst off air — it later began 24 hour broadcasting in 1997, with S4C simply broadcasting black screen and tone whilst off-air. |
ITV (1979-1988) Channel 4 Channel 4 Channel 4 is a British public-service television broadcaster which began working on 2 November 1982. Although largely commercially self-funded, it is ultimately publicly owned; originally a subsidiary of the Independent Broadcasting Authority , the station is now owned and operated by the Channel... (1982-1992) S4C S4C S4C , currently branded as S4/C, is a Welsh television channel broadcast from the capital, Cardiff. The first television channel to be aimed specifically at a Welsh-speaking audience, it is the fifth oldest British television channel .The channel - initially broadcast on... (1982-1992) |
||
| 1984-1999 | Testcard F is converted to an electronic format. On 4 October 1997, the BBC logo on the testcard was changed to match the current logo. It was removed from BBC One a month later due to the launch of BBC News which is now seen overnight on it. | BBC1 (1984-1997) BBC One BBC One BBC One is the flagship television channel of the British Broadcasting Corporation in the United Kingdom. It was launched on 2 November 1936 as the BBC Television Service, and was the world's first regular television service with a high level of image resolution... (1997) BBC2 (1984-1997) BBC Two BBC Two BBC Two is the second television channel operated by the British Broadcasting Corporation in the United Kingdom. It covers a wide range of subject matter, but tending towards more 'highbrow' programmes than the more mainstream and popular BBC One. Like the BBC's other domestic TV and radio... (1997-1999) |
 |
|
| 1999-2012 | Testcard J is released, replacing Testcard F. Testcard J is a modified version of F, with improvements including an improved centre picture and a dot in the white area at the top. In 2000, Testcard W is released, which is similar but formatted in 16:9 widescreen. Usage of regular testcards on BBC Two gradually started to decline during the early 2000s before regular use was discontinued in 2004. It is still seen occasionally on BBC Two, around mid-January each year. The usage of testcards in the United Kingdom will completely drop in 2012. | BBC Two |  |
Test patterns for photocopiers
A lesser-known kind of test pattern is used for the calibration of photocopierPhotocopier
A photocopier is a machine that makes paper copies of documents and other visual images quickly and cheaply. Most current photocopiers use a technology called xerography, a dry process using heat...
s. Photocopier test patterns are physical sheets that are photocopied, with the difference in the resulting photocopy revealing any telltale deviations or defects in the machine's ability to copy.
In numismatics
Television has had such an impact in today's life, that it has been the main motif for numerous collectors' coins and medals. One of the most recent ones is The 50 Years of Television commemorative coin minted on March 9, 2005 in AustriaAustria
Austria , officially the Republic of Austria , is a landlocked country of roughly 8.4 million people in Central Europe. It is bordered by the Czech Republic and Germany to the north, Slovakia and Hungary to the east, Slovenia and Italy to the south, and Switzerland and Liechtenstein to the...
. The obverse of the coin shows a "test pattern", while the reverse shows several milestones in the history of television.
Monoscope
Cathode ray tube
The cathode ray tube is a vacuum tube containing an electron gun and a fluorescent screen used to view images. It has a means to accelerate and deflect the electron beam onto the fluorescent screen to create the images. The image may represent electrical waveforms , pictures , radar targets and...
to generate, rather than display, a video signal. Each tube was only capable of generating a single video signal, hence the name.
Essentially similar in construction to an ordinary CRT, the monoscope contained a formed metal target in place of the phosphor coating at its "screen" end and as the electron beam scanned the target, rather than displaying an image, a varying electrical signal was produced generating an image from the etched pattern.
These were fragile, but had advantages over test cards, always being properly framed and in focus.
They fell out of use in the 1960s, as they were not able to produce color images.
External links
- The Test Card Circle Details of the UK's Trade Test Transmissions including the history of the BBC and ITA Test Cards, a look at the music used and full details about the Trade Test Colour Films shown from the late fifties to 1973.
- mire.project - Street art work about television test patterns
- TV Testbild - very informative, but in German language only
- TestVid test card video sequences - Synthetic video test card sequences with moving elements
- Burosch AudioVideo-Technology - advanced HDTV test patterns
- The Test Card Gallery
- Television Test Cards, Tuning Signals, Idents and Clocks
- Barney Wol's website has details of the development of UK testcards F, J and W
- 625.uk.com Flash Files - high quality Adobe Flash examples of almost all British test cards and station idents (the test cards are at the bottom of the page and include C, D, F, J, W and ETP-1)
- Irish TV Testcards - Pictures of Test Cards used by the Irish TV broadcasters RTÉ, TV3 and UTV.
- SVT test cards - Picture gallery of test cards from Swedish Television (SVT), in Swedish
- Russian Test Cards
- Maximum Testcardosity test cards' resources, history and galleries
- equasys Video Test Collection - MPEG-2, H.264, WMV and Flash video test sequences for PAL, NTSC and HDTV video formats.
- Pembers' Ponderings - Features detailed analysis of various test cards from the 30-line era to the present day, inclusive of a collection of various European test cards from 1967 to 1976.
- Taiwan TV Test card in 1990's
