English: 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.
This 1950 issue of Radio and Television News magazine would have the copyright renewed in 1978. Online page scans of the Catalog of Copyright Entries, published by the US Copyright Office can be found here. [1] Search of the Renewals for Periodicals for 1978 show no renewal entries for Radio and Television News. Therefore the magazine's copyright was not renewed and it is in the public domain.
Note that it may still be copyrighted in jurisdictions that do not apply the rule of the shorter term for US works (depending on the date of the author's death), such as Canada (70 years p.m.a.), Mainland China (50 years p.m.a., not Hong Kong or Macao), Germany (70 years p.m.a.), Mexico (100 years p.m.a.), Switzerland (70 years p.m.a.), and other countries with individual treaties.