Andy Warhol, Oxidation Painting, 1978. Copper metallic pigment and urine on canvas; 76 x 52 in (193 x 132 cm).
Also known as “Piss paintings,” Warhol worked on the Oxidation series from 1977 to 1978. He worked by spreading canvases out on the floor and coating them with a copper paint, which he would typically direct his assistants or Factory visitors to urinate on while the paint was still wet. Over time, the uric acid would oxidize the metal in the copper paint and create an attractively shimmering patina. Although the act of urination might seem to be the ultimate gesture of desecration, Warhol ironically insisted on the importance of artistic skill in their creation, explaining that “they had technique, too. If I asked someone to do an Oxidation painting, and they just wouldn’t think about it, it would just be a mess. Then I did it myself — and it’s just too much work — and you try to figure out a good design” (A. Warhol, quoted in I’ll Be Your Mirror: The Selected Andy Warhol Interviews, edited by K. Goldsmith, 2004, p. 327). Warhol particularly loved having his assistant Ronny Cutrone contribute these works, “because he takes a lot of vitamin B so the canvas turns a really pretty color when it’s his piss” (A. Warhol, quoted in The Andy Warhol Diaries, ed. P. Hackett, 1989, p. 55). He was so inspired by the painterly effects he achieved through the use of urine as a substitute for paint that he even experimented with brushing urine onto the canvas, although he gave up after finding it too difficult.