A Little Bit of History
British Television was of course the first in the world, and began on January 27th 1926 when Mr Logie-Baird first demonstrated that it was possible to transmit pictures using his mechanical scanning apparatus.
It wasn't until 1929 that the first experimental service was broadcast by the BBC in collaboration with The Baird Company. At this time transmission took place for thirty minutes per day using the Baird 30-line system.
It was around 1934 that the first simple patterns were generated to test the equipment. These consisted of a simple circle and line chart (which you will see later), which tested the picture ratio and the first wedge-shaped "frequency grating" for testing high-frequency response. It is worth bearing in mind that this could have been the time of the first "wide-screen" television, as the standard picture ratio at that time was 7:3. Unfortunately this was portrait, the image was much taller than it was wide. Early television recordings have been found and restored by Don McClean, check the links section for further information.
In November 1936, high definition television began. Baird had managed to improve his still mechanical system to 240 lines. However he faced competition from the Marconi-EMI electronic system, which provided 405 lines. The two systems were transmitted on alternate weeks, from Alexander Palace. It didn't take long for the government to decide that the 405 line system was far superior to the Baird system, and the Marconi-EMI 405 line system BBC Television Service was launched on February 8th 1937.
1937 saw the beginning of the BBC Tuning Signal. This was used to identify the station, and provide something for viewers to look at whilst waiting for the equipment to warm up. It was usually a simple pattern, which aided the viewer whilst adjusting the numerous knobs that controlled all of the fine tuning on their sets. Not that there were many viewers in 1937, it is estimated that only a few hundred people received these early transmissions.
1937 was also when the first electronically-generated test signal was broadcast. The "Art-bars" consisted of a large black cross on a white background.
Between 1939 and 1946 there was no television due to the war.
After the war, television took off again.3350
viewers tuned in to some new tuning signals and the first BBC
(There were programmes of course - I wouldn't want anyone to think that the BBC only broadcast test patterns!)
It was around this time that the BBC generated the first true "Test Card". Test Card A was designed to aid aligning studio cameras and testing response. It was also broadcast, aiding the field engineer who was setting up television sets. "Test Cards" are so called because the original ones were indeed cards, usually hand-drawn on large pieces of card. Typically they would measure 2ft by 3ft and a large camera would be placed in front. These test cards are usually referred to as "Opacities".
Later Test "Cards" were transparencies, varying in size from 1ft wide down to the 35mm slides common today.
There were also monoscopes, Cathode Ray Tubes with a metal plate onto which the image was etched. These were expensive to produce, and impossible to adjust. However, the generic term "Test Card" is used to describe all of these patterns, regardless of the medium used.
The rest? Well that's history. You will see a fair amount of that here in The Test Card Gallery.
Last Updated 29 Mar 2000