How to read TV2 test pattern

Press, Volume CXV, Issue 33873, 19 June 1975, Page 14

How to read TV2 test pattern

The test pattern is a series of electronic impulses which form a definite pattern on the screen. Television servicemen use this for the fine adjustments necessary to obtain the best possible picture, but it is also a guide to viewers. The same pattern applies for both black and white and colour sets. Correctly adjusted colour sets should show the colour blocks one third of the way down the circle in the correct order from the left — yellow, cyan, green, magenta, red and blue. Viewers may use these colour blocks to set the colour content of their picture. Final adjustments of colour are best made by comparing facial colour tones of people seen on the screen. The news readers who are filmed in ideal conditions are the most suitable for this. Do not change the colour during a film as film colours can be very unreliable. Use the test pattern for checking your reception but remember to let the set warm up for at least 10 minutes before starting to adjust the controls. Use the controls in the following order: Fine Tuning. — Watch the blocks .of vertical lines just below- the centre of

the circle as you adjust the fine tuning control. Black and white sets should be able to resolve at least the middle block into clearly defined vertical lines and preferably the extreme right block as well. Colour set owners should turn the colour off for this operation. With colour added, the two right-hand blocks will give a creeping effect. This is the same effect received in a film of car wheels which give the impression they are going backwards. The purpose of the fine tuning control is to line up the television receiver with the incoming signal. If this is not aligned properly, the picture becomes “soft.” lacking detail. In moving the fine tuning control with the test pattern, viewers should aim for a hard clear picture. Brightness and Contrast. —To check the brightness and contrast control, watch the row of rectangles below the blocks of vertical lines. The left-hand block should be black and that on the extreme right white. Those in between should be shades of grey. To make adjustments, turn the contrast control off. Adjust the brightness control until

a picture is just visible, then turn up the contrast until the blocks appear from black and white through even steps of grey. It may be necessary to make some further adjustments to the brightness control to get the best picture. The brightness control is most effective on the black parts of your television picture while the contrast control has the greatest effect on white sections of the picture. Colour or Saturation Control. — On colour sets the colour or saturation control is used to adjust the colour content.