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Television Test Cards, Tuning Signals, Idents and Clocks |
Background information and pictures of cards used in the UK and elsewhere |
Contents |
Test Card History |
More than just a pretty face |
Non-UK Test Cards |
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The birth of the test card |
EST CARDS have all but disappeared from tv
screens in the twenty-first century, certainly on old-fashioned
analogue terrestrial stations, where twenty-four hour programming
is the order of the day.
Even when there is a substantial break in the schedules the gap is often filled with headache-inducing trailers, a simple caption or selected pages from a teletext service. On satellite, however, where channels come and go apparently at random, there's often the odd test card or pattern to be seen - always electronically generated - and these introductory paragraphs are illustrated by some that I found knocking about recently in the Clarke Belt.
Test cards are still to be found on the UK terrestrial networks if you're prepared to wait, however. Once or twice a year the BBC tests its emergency rebroadcast system that is designed to bring programmes to your local transmitter even if all or part of the distribution network fails. On these auspicious occasions, usually at around two or three o'clock on a Sunday morning, a delegated engineer licks his thumb and forefinger and whips out a link on an equipment rack and BBC News 24 and The Open University are instantly replaced for an hour or so around the UK by Test Card J on analogue and Test Card W on digital. We provincials then also get a glimpse of the South-East regional Ceefax edition.
So what is the purpose of test cards and why are they so rarely used these days?
Today there's hardly room in tv schedules to squeeze a test card in sideways, and we are quite used to pressing a few buttons on a remote control to receive any number of programmes instantly. But fifty years ago things were very different.
For a start there was only one channel, and that only broadcast for a few hours in the afternoon and evening. Most people couldn't afford a telly, and they were hardly going to be persuaded to save up for one if the sets in the shops had blank screens. Even when you bought one, it wouldn't work straight out of the box. The dealer would have to install it for you, erect an aerial, and perform a complicated series of adjustments before you received your first picture.
Because sets relied on thermionic valves in those days and ran very hot, it was necessary to allow the circuitry to 'warm up' properly before your programme was due to start. Since this would most likely be the first show of the evening there had to be something on the screen to assure you that the set was going to work properly.
A simple caption would suffice, but how much better to have a display that would allow the viewer to tweak the user controls - brightness, contrast, horizontal hold, etc, that because of the poor stability of the electronic components inside the set required frequent adjustment.
The broadcasters too needed a test signal that would tell them that the network was functioning properly.
Of course special test generators were available that could be used to make accurate measurements of the performance of every aspect of the studio and distribution equipment, but again, how useful it would be to have a pattern that could give a rough indication of performance (or lack of it) from camera to screen.
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And so two siblings were born - the test card and the tuning signal. The tuning signal was a 'cut-down' test card that looked quite technical but not too frightening, and included identification and simple tests for brightness and contrast setting on the tv set. Thus it could be radiated prior to the start of programmes giving the viewer the confidence that his set was working, was tuned to the correct channel, and that the programmes were about to start.
The test cards on the other hand contained a more rigorous selection of patterns that were of use all the way through the broadcasting chain. The geometrical patterns allowed receivers, monitors and cameras to be adjusted to give a picture of the correct size and shape, while greyscales allowed the brightness, contrast and (in the case of cameras) gamma to be set correctly.
Gratings of fine lines enabled the focus of cameras and receivers to be checked, and fine tuning to be optimised. Larger black and white patches and needle pulses allowed aerials to be adjusted to obviate ghosting, and also showed up defects in transmission lines and vision circuitry. For a full technical description of the function of the various elements of some of the many UK test cards that have been used over the past fifty years, see More than just a pretty face...
All-in-all test cards were an invaluable toolbox for everyone involved in providing a television service at a time when test equipment was very expensive and programmes were few and far between. This altruistic approach has had its day though. As far back as the nineteen-seventies, when energy was suddenly at a premium, the BBC used to turn off its transmitters altogether when no programmes were scheduled and countered complaints from dealers and aerial installers by saying they were not in the business of providing test signals at licence-payers' expense, though they never went on to explain how one could install an aerial without a working transmitter to aim at.
The BBC's test cards are undoubtedly aesthetically as well as technically excellent. Each new one has had the same look to it, and all have been adopted by many other broadcasters in the world, starting of course with the UK's commercial independent television stations that began to appear in 1955. And it was a joy to see colour television sets tuned to Test Card F on BBC1, BBC2 and ITV in a dealer's showroom giving displays of almost identical quality.
Other countries had their own designs, of course; some taken up by several broadcasters, others unique to their own. The nineteen-sixties and -seventies were a golden era for receiving, identifying and photographing foreign test cards for those with such a disposition.
There are examples of long-distance reception on the Non-UK Test Cards page.
So how are test cards generated and transmitted?
There are basically three methods of making a test pattern. The obvious one - suggested by the name - is to draw or print the design onto a card and mount it in front of a television camera. A variation is to make a transparency and mount it in a slide scanner.
Whilst that technique is essential for testing the camera or scanner in question, it can lead to errors when the intention is to test the circuit or receiver.
A second way that was used early in the days of monochrome television was the 'monoscope'. That was a kind of camera tube that had the test pattern printed in carbon onto an aluminium plate that formed the anode of the tube. That produced much better signals for day-in day-out test card duty.
Thirdly there are the electronically generated patterns. Using simple electronic circuitry it's possible to generate a range of useful signals for testing circuits and receivers and such were in use by broadcasters and dealers from the start. But to make a comprehensive test card was a lot more difficult and it was not until the mid and late nineteen-sixties that they began to appear. The earliest was probably the Phillips PM5540 pattern generator as used by NOS in The Netherlands, and by others.
This was followed in the colour era by the Phillips PM5544, the IBA's ETP1 and the Telefunken FuBK pattern, amongst others.
Nevertheless, a few optical colour cards were used, notably of course the BBC/ITA/BREMA Test Card F, and that continued until the end of the century (from 1984 generated from a digital memory rather than a sandwich of mono and colour tranparencies mounted in a 35mm slide) until two revamped versions were introduced - the electronically generated Test Card J (4:3) and Test Card W (16:9) that included almost all the features of Test Card F, had the central colour picture digitally remastered from the original colour reversal transparency, and had additional tests required for digital operations.
Illustrations |
Test Card MusicI have not mentioned in any great detail the music that accompanies test cards and other captions. I suppose that is because my main interest in the cards was the identification of foreign stations received on a converted 405-line receiver. Its limited vision bandwidth was ideal for the weak signals that came in, but there was no way of demodulating the 5.5MHz or 6.5MHz frequency modulated audio, so test card watching was of necessity a silent business. However, the Test Card Circle Is a collection of enthusiasts who have dedicated themselves to identifying and obtaining copies of seemingly every record that was ever played behind every caption that was ever shown. |
HE OFF-SCREEN photographs of UK reception
were taken from production sets - a Ferguson 19-inch dual-standard
receiver and an EKCO 17-inch 405-line set in 1967-8 and a PYE
22-inch colour receiver rather later. Some of the non-UK cards I
photographed from receivers converted for 625-line VHF operation -
a 12-inch PYE 405-line receiver of 1950 vintage and a home-brew
20-inch 625-line only receiver constructed in 1970 from a design
published in Practical Television magazine.
The off-screen pictures of Test Card F were scanned from 35mm slides taken from the Forgestone 22-inch colour receiver kit in 1979, and all the twenty-first century screen shots are from a Sony WEGA 32-inch widescreen receiver photographed with a Hewlett-Packard Photosmart 318 digital 'snapshot' camera - a combination that results in frightful moiré interference patterns and some dubious focussing and exposure values.
The colour bars and some simple test patterns were recreated from scratch in Adobe PhotoShop. One or two video screen grabs have come my way, courtesy of Mark Carver and "Dantus" Paolo Pizzo, and other pictures, culled from various old books, magazines and leaflets, are included for completeness.
Because some of the off-screen and half-tone shots are a little fuzzy, I have reconstructed some of the cards from scratch in a graphics package. Click on the cards on the left of the page to reveal a full-resolution 405-line (500 x 375) or 625-line (765 x 575) version. (Choose "Open in a new window" in order to compare the reconstruction with the original.)
The 30-line era |
N 30 September 1929 the BBC was obliged to
allow John Logie Baird access to two London medium wave
transmitters for the purpose of experimental transmissions in the
30-line standard. These were produced by means of a 'Nipkow'
scanning disc - a 20-inch diameter aluminium wheel perforated at
the rim with thirty tiny holes, each one slightly nearer the centre
than the last, so that a 'raster' of thirty vertical lines with an
aspect ratio of 3:7 was produced. To get an idea of the scale,
imagine a clock face. The height of the scanned picture would be
represented by the distance between the fourteenth and sixteenth
minute marks. The pictures produced (by viewing a neon light
through the disc) were dark, small, flickery and slightly
curved.
On 22 August 1932 the BBC took over responsibility for the transmissions, having installed a proper studio and control room, operating with equipment that used mirror drums instead of Nipkow discs. Receivers using that technology were also introduced, leading to larger, brighter pictures with straight verticals. The BBC 30-line transmissions continued until September 1935, and included programmes and test patterns. Because of the technical limitations, only the head and shoulders of one actor could appear on screen at a time. To change shot, a large chequerboard was slid in front of the camera whilst another actor moved into place.
The captions were scanned by means of a second camera mounted in front of a carousel carrying a dozen caption cards. The test patterns were very simple and were not assembled into a composite card as they were to be with high-definition standards.
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The 405-line era |
HE FIRST 405-line era began at 3pm on
Monday 2 November 1936 with the start of the official BBC
television service from Alexandra Palace and ended abruptly on
Friday 1 September 1939 two days before the outbreak of the second
world war. At 3pm on Friday 7 June 1946 programmes resumed, almost
as if there had been no interruption. The end came on Tuesday 1
January 1985 - albeit a day later in Scotland because of the bank
holiday there. Apparently there were no complaints about the
closedown - BBC1 and ITV had been available in most areas for many
years on 625-line UHF in colour, and it seems that almost everyone
had equipped themselves with a 625-line receiver by 1985.
More details of the UK 405-line service including some ITA transmitter coverage maps from 1967 may be found on the UK 405-Line Television Network section of this web site, and technical specifications and more detailed history are on World TV Standards.
This section illustrates some of the test cards that were in use on the UK 405-line standard, though I have included UK 625-line monochrome cards, and some international 'standard' cards from the same era. There are separate sections for colour and widescreen cards, including some from non-UK broadcasters. Further examples of non-UK test cards and captions, a number of which I received and photographed myself here in Sheffield, can be found on the Non-UK Test Cards page.
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Between 2 November 1936 and 7 February 1937 the EMI 405-line system alternated week-by-week with the Baird 240-line 25 frames per second system on a trial basis. The Baird system had an aspect ratio of 4:3, while that of the EMI system was 5:4 until 1950. Since Test Card A has a definite 4:3 aspect ratio it could be inferred that it was used for the Baird system but in fact all the cards I have come across seem to be designed for 4:3, including some shown below which were introduced in 1946 and 1949. Just above the black circle in Test Card A is a set of fine horizontal lines at a pitch of about 1/360 of the height of the card. The 405-line picture (377 lines high) might just have resolved these, but the Baird 240-line picture would not have. A 405-line receiver would not have resolved the '3 MC' vertical bars since the transmitted vision bandwidth was 2.5MHz, but they would have shown up on studio monitors. The video frequencies used by the 240/25 system were only a quarter of those required by 405/50 though. A mere 857kHz would have sufficed for the Baird system, which means that Test Card A was certainly not designed for that standard. Despite the scarcity of programmes at the time (a couple of hours in the afternoon and evening) Test Card A was rarely seen. What was more often transmitted, continuing into the 'fifties and 'sixties, was this first-ever electronic test pattern known as the cruciform (or 'art bars' - short for 'artificial' - in the trade). Although extremely simple to generate, it had several functions: firstly as check on picture centring, secondly as a test of high frequency response (the vertical edges of the cross should be sharp) and thirdly to indicate low frequency response (the black and white areas should be uniform, and not turn grey towards the right). Also from that period - around 1938 - is this fragment of an early BBC tuning signal cum station ident. |
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However, the firm Cathodeon introduced a range of monoscope test patterns labelled B to G. C and G were the standard cards shown below, but D, E and F weren't. Pattern B was this view, probably of a Cambridge college, since Cathodeon were a subsidiary of Pye which was based in that city. Test Card B it ain't, but it's the nearest thing with an official B designation that we have. |
 Eric the half-a-B |
Half a loaf...Simon Vaughan, Archivist of the Alexandra Palace Television Society, has kindly sent me a copy of this photograph, taken during a production of "Laburnum Grove", produced by Ian Atkins with sets by James Bould and transmitted in the late 1940s. The photograph was taken by Tom Edwards, Master Carpenter at Alexandra Palace, as a record of his own work, and clearly shows a large test chart on an easel at the bottom left-hand corner. I have straightened out the photo to reveal half of Test Card B. Click on the image on the left for a reconstructed version based on written descriptions, for which I have guessed at the appearance of the spectral response test, having picked colours similar to those found on a modern panchromatic response chart. Like Test Card A above, Test Card B was designed primarily as a studio-based chart for the alignment and adjustment of cameras, rather than domestic receivers, and so was probably never put to air. Neither has any peak white indication or proper contrast wedge and the grey background would have been adjusted for around 80% white on the waveform monitor, as in the reconstructions, in order to avoid overshoot on the frequency gratings. The 'letterbox' probably comprised a strip of very low reflectance material such as velour that acted as a black-level reference for the cameras as it would appear darker than the other markings on the chart. |
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UNING SIGNALS were a feature of
early television, being radiated just before
programmes started each afternoon.
The first pattern is a sort of 'Test Card C Light',
retaining the black/white concentric circles,
needle pulses, greyscales and a frequency grating.
The lower ITA pattern, used throughout the 'sixties until the introduction of colour,
has similar features juggled around,
and was generally known as the Picasso pattern, for obvious reasons. |
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In July 1949 this caption was replaced with a similar one containing a clock, but still cunningly retaining the circle and frequency gratings. Later in 1949 Corporate Identity raised its head and the card was redesigned to incorporate 'wavy' greyscale bars (at least someone had the good sense to persuade the designer not to have the 'waves' running vertically!) and a more modern typeface was introduced. The earlier font was none other than gill sans to which the BBC has returned wholesale for the new millennium. It was originally designed for the signage and publicity for the London Underground by sculptor Eric Gill. He it was who carved the figures of Prospero and Ariel for the frieze around Broadcasting House in Portland Place. After an outcry he took his chisel to the pair's protruberances, which had been adjudged to be too prominent when viewed from ground level. 
In my childhood I used to have a small plastic money box in the shape of a Pye V4 console model tv set which had a version of the 'wavy' tuning signal on its screen. Unfortunately I lost it many years ago, but Tony Bryant still has his and he's sent me a picture of it. Thanks, Tony. There is something puzzling about these early charts. As mentioned above, the aspect ratio of the 405-line standard was 5:4 until 1950, when it was changed to the present-day ratio of 4:3, yet all the charts above with castellations and circles are clearly 4:3. Resizing them to 5:4 gives distinctly tall circles. Very odd. |
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The central 'eyelids' - orientated north-south and east-west in this shot - rotated in the plane of the caption like clock hands, one going clockwise, the other anticlockwise. Meanwhile the surrounding circle had a metal ring mounted on bearings between the arrows at top and bottom and it also rotated, sweeping out a hemisphere from right to left as it moved in front of the globe. The whole thing repeated about once every five seconds. Very simple and hypnotic, especially when screened for extended periods as a potter's wheel substitute. Click on the still for a brief Windows Media Viewer animation, courtesy of Mark Carver. The angel's wings device (the brainchild of designer Abram Games) was also used on these similar static cardboard tuning signal captions introduced on 19 August 1955 and 16 June 1956, still incorporating circles, castellations, greyscales and frequency gratings.. |
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EST CARD C, dating from 1947 was almost the
trade mark of the BBC and ITA during the fifties and early sixties
as it appeared in shop windows up and down the country. As a
phrase, "Test Card C" lingered on in the national psyche long after
it disappeared from screens in 1964. There's a full technical
description of Test Card C on More than just a pretty
face... |
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 VARIANT of Test Card C was used on BBC2,
with frequency gratings suitable for 625-lines. The intention was
to use Test Card D on 405-lines and Test Card E on 625-lines, but
BBC engineers were unhappy with the appearance of the TCE frequency
gratings and so this card, which never sported an identification
letter, was retained until the start of the colour service in July
1967. There's a full technical description of this variant of Test
Card C on More than just a
pretty face... |
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HIS 625-LINE version of Test Card C was
called Test Card G, but was only ever radiated in the UK in the
non-G form shown above, though it was used by other broadcasters
around the world. The BBC used the designation "Test Card G" for
their version of the Philips PM5544
625-line colour electronic test pattern from the 1970s onwards.
There's a full technical description of Test Card G on More than just a pretty
face... |
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HIS WAS the first 625-line test card to be
seen in the UK. It was radiated by the BBC from Crystal Palace on
channel E44 from 1962 to 1964 prior to the official start of BBC2
on 20 April 1964 on E33. The design was adapted by the BBC from the
SMPTE 525-lines card, with the addition of a greyscale and finer
resolution wedges. There's a full technical description of the
SMPTE test card on More
than just a pretty face... |
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FTER THE introduction of BBC2 on 625-lines,
Test Card D was used on BBC1 and ITV 405-lines, replacing Test Card
C. There's a full technical description of Test Card D on More than just a pretty
face... The BBC1 channel B2 transmitter radiating the card
pictured here was Holme Moss, now used only for FM radio. When the
ITA split the north region, allocating franchises to Granada and
Yorkshire Televison, the BBC also split its coverage. Holme Moss
(still transmitting to both sides of the Pennines) carried BBC
Leeds, but outraged Lancastrians could retune to the Winter Hill
Band III B12 transmissions for their own flavour of Look
North. |
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HE ITA test cards were originated from
flying-spot scanners at the main transmitters and hence carried the
transmitter names and channel numbers. Each transmitter had a stock
of slides with different test patterns and captions for most
eventualities. They also had a pile of 78rpm records containing
audio announcements and apologies. The music accompanying the test
cards was from microgroove discs, however, and very high quality -
often classical selections as opposed to the lighter BBC
offerings. |
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 INTER HILL, Emley Moor's twin serving the
area to the west of the Pennines, was a very rare visitor indeed to
Sheffield, as the Pennines are an effective boundary to Band III
television signals. This weak B9 signal was received during a
tropospheric opening. |
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HEN THE new franchises began in 1968, the
identification was changed from transmitters to operating
companies. In 1969 the 625/405-line standards converters were moved
from studio centres to transmitter sites, and Test Card F was used
on both standards, originated in 625-line PAL colour at the
studios, so these Test Card D shots must be quite rare. The Anglia
transmitter was Belmont - received very well on both VHF and UHF in
Sheffield. It changed over to carrying Yorkshire Television
programmes in the seventies, though it has always carried BBC North
(Manchester, and after the split, Leeds) on its BBC channels. |
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HE 625-LINE version of Test Card D was Test
Card E, but was hardly, if ever, radiated in the UK. It was used by
other broadcasters around the world, however.
There's a full technical description of Test Card E on More than just a pretty
face... |
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This first one is the SMPTE (Society of Motion Picture and Television Engineers) test card mainly used on 525-line transmissions, though its resolution wedge calibrations are valid for any line standard. Despite this the BBC produced its own version for very early tests of its 625-line uhf transmissions between 1962 and 1964. There's a full technical description of the SMPTE test card on More than just a pretty face... |
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 ARCONI RESOLUTION Chart Number 1 was so
successful that they never needed to release a sequel... |
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HIS IS the RMA (Radio Manufacturing
Association) Resolution Chart 1946. It was used by many
broadcasters even after the introduction of the 1956 version,
below. |
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HE RMA changed its name to RETMA (Radio,
Electrical and Television Manufacturers Association) prior to
bringing out this new design, called the RETMA Resolution Chart
1956. In 1975 it became known as the EIA (Electrical Industries
Association) Resolution Chart. |
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 INALLY HERE is a European design, the
Telefunken test card T05. As well as these optical charts, there
have been several electronic monochrome and colour test patterns,
mainly from Philips. Several examples may be found in the colour section and on the Non-UK Test Cards page. |
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HIS EARLY electronic pattern was simply
known as the "EBU monochrome test pattern" and was mainly used for
testing and identifying circuits, as the accompanying shot of an
ITV gallery during the 1966 World Cup shows.  Some European broadcasters
used it on air however, often with an identification in the black
rectangle. This transmission was from TVE in Spain photographed in
1969 from a receiver with a much reduced IF bandwidth so that only
the top two rows of frequency gratings were resolved.
There are more examples of long-distance reception on the Non-UK Test Cards page. |
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Camera Test Transparency No 50, from June 1956, was designed to assess the colour response of monochrome camera tubes. When viewed on a monitor or oscilloscope, the amplitude of each of the three coloured gelatine areas on the transparency could be matched to one of the neutral step wedge blocks. A more precise pattern, designated No 53, using six colours, was introduced later. Camera Test Transparency No 51 used an Ilford test picture as a basis for assessing overall camera performance on a monitor. In addition sinusoidal frequency gratings (obtained by photographing test waveform patterns displayed in a film recording apparatus) and contrast step wedges were used for technical assessment. Test Card No 52 was identical except that the frequency gratings were designed for 625- rather than 405-line working. The production of these test slides was extremely complex and involved using several separations to make the master negatives. Another contemporary transparency was No 56, comprising two complementary patterns designed to align two slide or film projectors optically multiplexed into one camera channel. Unnumbered charts included a colour camera registration chart, consisting of a pattern of fine white lines on a black ground. When the output was viewed on a colour monitor coloured fringeing was visible where the camera registration was in error, and the pattern was designed so that adjustment in critical areas (centre, corners, centres of edges)was more easily accomplished. Another unnumbered chart was the telecine hop and weave pattern in which separate exposures, in two passes, of two halves of a vernier scale allowed the amount of picture movement from frame to frame in a camera or printer to be measured. Colour Camera Greyscale Chart No 57 incorporated an 'ultra black' section - basicially a hole cut in the chart with a matt black box mounted behind, as well as precision logarithmic complementary contrast stepwedges. Note that even for colour televison cameras, most optical test material is monochrome only. There's not much you can learn from putting coloured blobs in front of the lens, though special compositions incorporating natural and flesh tones are useful in assessing the performance of the camera once it has been adjusted. The BBC Test Card No 61, Flesh Tone Reference, was introduced in 1977 as a standard reference for television cameras. Previously only models (live or inanimate) had proved satisfactory, but even then it was difficult to ensure standard lighting conditions. The BBC 62P colour bar chart, developed with WR Royle and Sons, used special pigments to give high-saturation colours. |
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ELEVISION TRANSMISSIONS are not the sole
province of professionals. These ARRL (American Radio Relay League)
and BATC (British Amateur Television Club) test cards were made
available to licensed members of the Amateur Radio Service for use
in slow- and fast-scan contacts. The operator would add station
details, such as callsign and location, to the card. |
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 OWADAYS THERE are more cameras out in the
streets than there are in television studios, and here is a test
card just for them. Developed by the Police Scientific Development
Branch for measuring closed circuit television camera performance,
it includes a camouflage cover that meets Ministry of Defence
specifications. |
Colour |
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The test card was mostly light (~80%) grey, but the three bands across the centre circle were red, green and blue, and the triple blocks of colour at the centre of each set of castellations were the complementaries yellow, magenta and cyan, as shown in the version I have reconstruction which you can see if you click on the card on the left. The black quadrants in the corners each had three white spots as a check on dynamic convergence, and the centre black circle had more for static convergence. The frequency gratings were 3MHz (upper) and 2MHz (lower). The subcarrier frequency was 2.6578125MHz, so there would have been some cross-colour patterning at these two frequencies. The scale below the circle was probably a test for reflections, and seems to have been drawn on a separate peice of paper and stuck on slightly off-centre. Each graduation represents 5µs (a path length of 1 500m, around a mile). The width of the card represents 80µs.
ABC Television, one of the ITV companies, also experimented with 405-line colour, using all three of the then available standards - NTSC, SECAM and PAL. They were in favour of introducing 405-line colour on ITV alongside the 625-line BBC2 colour service (as indeed were the BBC for a time, for BBC1), which would have made televison sets almost impossible to design, manufacture, adjust, afford or watch, judging by the dreadful performance of the monochrome dual-standard sets that were introduced. In 1962 the BBC began tests of 625-lines on uhf using two channels simultaneously - E34 and E44 - in both monochrome and colour. NTSC tests were radiated in February 1963 followed by SECAM tests in March of that year. The tests continued until the official start of BBC2 on 20 April 1964 on E33. PAL tests were conducted during BBC2 trade tests during the afternoons beginning on 24 May 1965, but after a few months these were moved to after the nightly closedown. Early colour camera were quite large. The shot on the left shows an Image Orthicon camera in use during an experimental transmission from the Alexandra palace studio in 1956. The camera used three 7.5cm tubes, as opposed to the 11.4cm tubes found in monochrome cameras of the day. The light path was split using dichroic mirrors. |
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Shown here is the original version of Test Card F transmitted on BBC2 only, from the start of the experimental colour service in 1967. The numerals listing the frequencies of the adjacent gratings were soon removed because the card was to be used on both systems, being standards-converted at the transmitters for 405-lines. At the start of the BBC2 colour service the card alternated with full-screen colour bars, but in later years twelve lines of colour bars were instead inserted at the top of the test card, obscuring most of the cyan and black castellations. |
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Occasionally the character generator was used to superimpose an informative caption over the test card, and so the original ident on the card could not be obscured. In this example it is being used to announce some audio engineering tests. Other instances of added text that I can remember are when the Radio 4 long-wave transmitter was out of action for a length of time and Radio 4 programmes were broadcast on the tv audio channel. When Apollo 13 had a problem, regularly updated announcements were made by the same method, before a programme giving full coverage could be got on the air. That was in the days before teletext newsflashes and twenty-four hour rolling news channels of course. The blue strap at top right of the pictures is the Ceefax clock courtesy of the Wireless World teletext decoder installed in the Forgestone receiver from which the shots were taken. See the Teletext Remembered section of the site for all the gory details. In these days of high-resolution anti-aliased computer graphics, it is hard to remember that not so long ago most captions were made with dry-print or hot-press characters on board and photographed by a tv camera (or photographed onto a 35mm slide and scanned). Although bit-mapped character generators were available, they had a distinctly 'blocky' look to them and were frowned upon in broadcast circles. The BBC character generator seen here was not digital at all, but analogue. The shapes of the characters were made by electronic circuits that generated straight lines and ellipses, chopped up and repositioned to give the relatively smooth glyphs shown in the enlargement. The main function of the character generator was the production of subtitles in programmes for the deaf, and also some foreign language films, though the latter tended to use optical titles until better fonts were available electronically. |
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ERE ARE the four BBC colour electronic test
cards F, G, J and W and the IBA electronic test
pattern ETP1 which was introduced in 1979. There's a full
technical description of each of the UK test cards on "More than
just a pretty face...". Click on the cards below to read them.
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HE PHILIPS PM5544 electronic colour pattern
has been the test card of choice for most colour broadcasters since
the late 1960s. It has had several variations, this photograph
being taken from a recent analogue satellite transmission. There's
a full technical description of the PM5544 pattern on More than just a pretty
face... |
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HIS ELECTRONIC card, which first appeared
in the nineteen-sixties, is generated by the Telefunken FuBK
(Funkbetriebungskommission, the German
Television Service Commission) pattern generator and was used
extensively in Germany and some other countries. It is one of the
few patterns that lacks castellations or arrows to mark the
extremities of the picture. |
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There are more examples of long-distance reception on the Non-UK Test Cards page. |
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 HANNEL FOUR when it was testing in 1982
radiated the IBA's ETP1 test pattern, but this monstrosity,
captured in December 1996, was the nearest we ever got to a test
card on the Channel 5 network. It's designed by some meeja-skool
whiz kid who once saw some colour bars and thought they looked
k3wl. Absolutely useless as a test pattern of course since the
colours are meaningless, and since Channel 5 was conceived as a
twenty-four hour station there has never been a spare moment since
the opening day to radiate a test card so none was ever
commissioned. The same could be said about this effort from ITV
Digital I suppose, but it was just a joke dreamed up when the
moribund digital terrestrial subscription service was about to
close down in the spring of 2002. |
Widescreen |
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The MAC (Multiplexed Analogue Component) standard is described briefly on World TV Standards. |
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I have attempted to scale and position all these widescreen patterns so that the 12:9 points are aligned more or less vertically. |
The Television Test Cards Web Page is now closing down for the night.
Please do not forget to turn off your computer before putting the cat out and going to bed. Hmmmmmmmmmmmmmmmmmmmmmmmmmmmmm...
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Mike
Brown/MB21/Ether.net
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Compiled by Alan Pemberton
Sheffield, South Yorkshire, England
Email me
O WHAT of Test Card B? It was
similar to Test Card A, but with the letterbox shifted to the top
in place of the central frequency gratings and replaced with a
strip of coloured squares from an Ilford panchromatic response chart at the bottom. This was to assess the
spectral response of the camera, but it produced a non-linear
brightness staircase on the picture which confused technicians. No
complete copy of this card appears to have survived.
