If you are old enough to remember television with a bedtime, you remember this: the last program of the night ended, and instead of going dark, the screen filled with a strange, frozen picture. Circles within circles. Bars of gray. Crosshairs and wedges. And, in the middle, a face.
For American viewers, that face was usually the same one: the drawing of a Native American man in a feathered headdress, done in black and white and mounted in the center of a test pattern that looked like an eye exam chart. It was called the Indian-head test pattern, and it was introduced by RCA in 1939. It was not a photograph of a card. It was generated as a video signal by a special tube that had the image permanently baked onto its target plate, and it was designed for engineers, not viewers — every circle and wedge and gray step was there to let a technician check that the picture was centered, sharp, and correctly toned.
But the engineers were not the ones who saw it most. Everybody did. In America, the pattern became familiar from the late 1940s onward, because it was what appeared after a station formally signed off for the night, often just after the national anthem. It was the last thing on the screen before the screen went to static. In Canada, the pattern followed the Canadian anthem. Versions of it ran in a great many other countries, sometimes with the face replaced or removed entirely. It was, for a couple of decades, the most-viewed image in the world that nobody actually wanted to see.
Nothing about it was entertainment. It was the opposite of entertainment: the visual equivalent of a dial tone. A test pattern on the air meant, precisely and only, that there was nothing on the air. Which is exactly why it is remembered. It is one of the rare images that carried a single, clear message — nothing here — and that the whole culture learned to read without being taught.
When color arrived, the black-and-white face was gradually replaced by color bars, the vertical stripes of red, green, blue and their combinations that let engineers align color on a set. Color bars are still in use today, as a reference, long after nearly everyone stopped watching broadcast television the old way. Meanwhile the sign-off itself — the pattern, the anthem, the silence — began to disappear. Twenty-four-hour cable and then twenty-four-hour everything made the idea of a station having a bedtime quaint. By the 1980s and 1990s, in much of the world, television simply never stopped, and so there was never a night to sign off from.
In Britain there is a parallel icon with a face of its own. Test Card F debuted on the BBC in 1967, for the arrival of color, and its central image is a girl playing noughts and crosses with a clown doll. The girl was Carole Hersee, the daughter of the man who led the team that designed the card. A person was chosen for the center for a very practical reason: human skin is the hardest thing to reproduce correctly in color, so a face is the best possible test. She has been called, half-jokingly, the most-shown face in the history of British television, and it is probably true.
There was one more appearance, late in the story. When American television switched from analog to digital in 2009, a number of stations chose the old Indian-head pattern as the very last thing they transmitted in the old format — a deliberate, almost sentimental goodbye. After that, the pattern moved off the screen and into memory, and into the odd corners of the internet, where people who never once watched a sign-off still somehow recognize the face.
Today, if a channel goes quiet, you get a blue screen and a few words, or nothing at all. It is more efficient and less strange. But the test pattern had a quality that the blue screen does not. It was made to be looked at, by people whose job was to fix the picture. The rest of us just happened to be there at the end of the night, watching a machine examine itself, one last circle before the snow.
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