In the central gallery housing Hockney’s drawings is a crayon portrait from 1974 of Andy Warhol, looking frail and a little lonely on a stuffed green chair in Paris. A comparison between the two artists, who were friends, is instructive. The parallels are clear: both gay, blond icons of Pop art, both protégés of Henry Geldzahler, both sons of working class parents, both prolific and witty writers. But here the similarities end, and the two artists begin to seem like inversions of each other. After the initial erotic frenzy of his work from the 1960s, the sexuality in Hockney’s art largely retreated behind discreet visual conventions; sex in Warhol was comparatively hardcore, particularly in his films. Likewise, the theme of death is explicit in Warhol and circumspect in Hockney. Warhol’s narrative voice is arch and elusive, willfully blank; Hockney’s direct and incisive, and at times, almost doggedly earnest. But the most striking zone of commonality and difference has to do with the way the two artists treated the issue of mechanical reproduction.