The original version of Big Jim McLain is set during the hysterical Red scare of the McCarthy years, and follows the exploits of an American government operative who is sent to Hawaii to root out a communist cell. Marijuana plays no part whatsoever in the original story, but the film's Italian distributors felt that its plot had little relevance to audiences there, so when the film was dubbed the dialogue was adapted so that John Wayne's government agent appears to be cracking down on the illegal drug trade rather than undercover communists. It was this aspect of the film that Luigi Martinati chose to depict in the Italian poster campaign.

Luigi Martinati (1893-1984) had a prolific career in film poster art. Born in Florence, he moved to Rome in 1911 and started as an artist's apprentice. He became the manager of one of the leading advertising agencies in Rome, where he worked for a number of film companies, notably Warner Brothers. In the mid-40s, he joined forces with two other giants of Italian poster design, Anselmo Ballester and Alfredo Capitani to form a company devoted exclusively to the production of film posters. Between them, the three artists produced an endless stream of striking, memorable images. Martinati's personal style is characterised by a large portrait shot combined with a smaller scene in the foreground.