Norman Hartweg, Paul Foster, Can You Pass the Acid Test, 1965 (reprint). Los Angeles-based artist and underground journalist Norman Hartweg collaborated with Merry Prankster Paul Foster to create this seminal image. Hartweg’s collage meshed perfectly with Foster’s busy cartoons to create one of the most prized images in the San Francisco poster renaissance.

The dawn of psychedelic posters coincided with the birth of the Dead and the advent of the Haight-Ashbury. Although the Haight community had been coalescing for some time, starting in the late fifties with Beat expatriates fleeing North Beach, it was not until the first rock concerts in the fall of 1965 that the proto-hippies of the Haight and the more attuned and perceptive members of the larger Bay Area bohemian/artistic/intellectual scene realized that there was something happening.

One of the primary catalysts was novelist Ken Kesey and his group of fellow psychedelic explorers, the Merry Pranksters. They hatched idea of the Acid Tests—public multimedia parties featuring film, music, sound, and light—while LSD-25 was still legal, and the Acid Tests were designed not so much to harness but unleash the potential of the extraordinarily powerful hallucinogen.

Psychedelics were about learning to see again, and in the Haight, that also meant seeing the magic in everyday life, from the way the fog moved in from the Pacific to the artisanry of a fellow hippie’s crafts, laid out on the sidewalk—or the cartoons and images Norman Hartweg and Paul Foster (1934–2003) combined for their famous poster advertising the Muir Beach Acid Test. This image is a later reissue, one of several published by Kesey and his son Zane in the 1990s that adapted Hartweg and Foster’s image with different backgrounds, colors, and paperstocks.