TV Testcard Baseball T-Shirt

A test card, also known as a test pattern, is a television test signal, typically broadcast at times when the transmitter is active but no program is being broadcast (often at startup and closedown). Used since the earliest TV broadcasts, test cards were originally physical cards at which a television camera was pointed, and such cards are still often used for calibration, alignment, and matching of cameras. The most famous British test card is Test Card F which incorporates a colour photograph of Carole Hersee (daughter of BBC engineer George Hersee) playing noughts and crosses with a Bubbles the clown, used on the BBC and ITV from the beginning of colour broadcasts in the late 1960s