Wes Wilson, who designed Bill Graham’s first Fillmore Auditorium ads, was “probably the most influential designer of hippie posters,” according to Graphis magazine in 1968. In this poster, he embedded a photograph of the Butterfield Blues Band into a background of swirling shapes, unexpected colors, and odd lettering. Wilson recalled selecting his colors from hallucinatory experiences with LSD.

His manipulation of words was particularly trendsetting. Wilson liked working freehand and filling up the space with ornament, so when he encountered a book of turn-of-the-century Viennese Secessionist posters, he adapted their sinuous lettering to his own art. “Playing with foreground and background,” he noted, “helped me work out patterns and shapes.” Much to Graham’s frustration, Wilson’s habit of burying pertinent information underneath “oozes and ebbs and flows and liquidy movement” often made his (and subsequent designers’) posters illegible, but it did encourage viewers to stare longer.