This is a fine example of Victor Moscoso’s use of opposing colors to create a vibrating effect by introducing uncertainty into the eyes of the viewer. The image itself was a solarized black and white photo by Belgian surrealist Raoul Ubac that was borrowed and psychedelicized by Moscoso.
Only first original pre-concert printings of this issue were produced, no second printings exist, and it was the 8th produced by artist Victor Moscoso in his retinal-burning Neon Rose series. It was printed in 1967 for a run of shows at the Matrix in San Francisco. By the end of 1966, Moscoso realized that the posters he and others were creating to advertise the dance concerts proliferating in San Francisco were admired – and sellable – works of art and thus could not only advertise the concert but also be sold later to adorn hippie walls. So Moscoso went to the management of The Matrix and offered to create and print their posters for free, as long as he could print extras and sell them.
Otis Rush Jr. was an American blues guitarist and singer-songwriter. His distinctive guitar style featured a slow-burning sound and long bent notes. With qualities similar to the styles of other 1950s artists Magic Sam and Buddy Guy, his sound became known as West Side Chicago blues and was an influence on many musicians, including Michael Bloomfield, Peter Green and Eric Clapton. Rush was left-handed and played as such; however, his guitars were strung with the low E string at the bottom, upside-down from typical guitarists. He often played with the little finger of his pick hand curled under the low E for positioning. It is widely believed that this contributed to his distinctive sound. He had a wide-ranging, powerful tenor voice.
As to the image that Moscoso used, it was created in 1936-37 and titled Penthésilée. In the Trojan war, Penthesilea was a Thracian woman warrior, an Amazon and daughter of Ares, who came to help the Trojans. She arrived with twelve other Amazon warriors. After a day of distinguishing herself on the battlefield, Penthesilea confronts Achilles. Achilles kills her, but after taking off her helmet, he falls in love with her.
As The Met writes, “Ubac was active in the Surrealist movement during the late 1930s. His photographs appeared frequently in the Surrealist publication "Minotaure," alongside photographs by Brassaï, Boiffard, and Atget, as accompaniment to texts by Breton and other Surrealist poets. Surrealism's efforts to tap the creative powers of the subconscious led them through a landscape of dreams, chance, sexual fantasy, and madness.” Sounds like a pretty good starting point for psychedelic imagery!