The famous RCA Indian Head television test pattern used on many television stations during the 1950s and 1960s, with its parts labeled explaining what each part of the pattern was used for. Test patterns are still images often transmitted by TV stations when no program is on. The parts of the pattern were used to measure the resolution of the signal, and to align the transmitter or receiver to get the best picture. This pattern was used with the old analog NTSC video transmission standard employed in the US before 2000, so many elements of the pattern would not be of use for modern digital HDTV pictures.