Andy Warhol announced his disengagement from the process of aesthetic creation in 1963. Like other Pop artists, Warhol aligned himself with the signs of contemporary mass culture. He used found printed images from newspapers, publicity stills, and advertisements as his subject matter and adopted silkscreening, a technique of mechanical reproduction, as his medium. In his Retrospectives and Reversals of the late 1970s, Warhol took up as his subject his own earlier artworks, resurrecting many of the most well-known silkscreened images of his Pop period—Campbell's soup cans, Elvis, cows, the Mona Lisa—and combining them or reversing their colors to produce negative images. One Hundred and Fifty Multicolored Marilyns is one of the largest of these works and features one of the artist's best-known celebrity subjects. Marilyn Monroe had first appeared in Warhol's work in 1962, the year of the actress's death; that year alone, he had made numerous silkscreened paintings using the same iconic photograph of the doomed starlet. The quantity of repetition in One Hundred and Fifty Multicolored Marilyns expresses most clearly the potentially unlimited replication of this—or any—image. At the same time, the reversed images have a haunting, ghostlike quality, lending this painting a mood of retrospection that is characteristic of much of the artist's late work.