Machines · Study 076
Test Card
A late-night television test pattern with colour bars, a grey ramp, scanlines, speckled static and picture tears where your pointer touches.
What you're looking at
The picture is built in layers. Seven colour bars and a stepped grey ramp go down first, then a centre circle with the station name and the time. On top come dark scanlines, a pale band that rolls down the screen, random speckle, and now and then a strip of the image copied sideways to mimic a loss of horizontal sync.
The idea behind it
Broadcasters transmitted test patterns outside programme hours so engineers and viewers could adjust their sets. The bars are in descending order of brightness, which makes errors in colour decoding easy to spot, and the circle shows at a glance whether the picture is being stretched.
Try this
Move the pointer over the screen to pull a tear through the picture at that height.
