In the 1940s, the BBC began using patterns specifically designed to assist with aligning studio cameras and testing response. In addition to being used off-air, these designs were also broadcast, and became a useful tool for the TV trade, when setting up domestic TV installations. Initially, the designs were hand-drawn on large pieces of card, typically 2ft x 3ft. Hence the term “Test Card” was coined. Later these patterns were put to air using 35mm slides and later again, were generated electronically. The term “Test Card” became the common term for these special designs, irrespective of the means by which they were put to air.