This 50 centimo stamp (Sc #581) from Spain's 1936-8 definitive series depicts Spanish Baroque painter Diego Velasquez (1599-1660). The pose on the stamp is very similar to the one (shown here) on a detail/close-up view of a 1643 self portrait by the artist.
From wikipedia, "Diego Rodriguez de Silva y Velasquez was the leading artist in the court of King Philip IV and of the Spanish Golden Age."
Here is the USA's May 13, 2008, 42c commemorative featuring American singer Frank Sinatra 1915-98). Sometimes "Sinatra" was signed in one part, as on the stamp, and other times there was a break; it was in two parts.