Alice Neel: Painted Truths, Whitechapel Art Gallery, London

She was the great survivor of American art – and, just maybe, the portraitist who got the measure of Andy Warhol

Three things about Alice Neel's portrait of Andy Warhol strike you straight away: the unpleasantness of its subject's flesh (saggy, fish-like, opalescent); the fact that Warhol is wearing a surgical corset over massive abdominal scars; and, last but perhaps most arresting, that his eyes are closed.

The idea of the eyes as windows to the soul is a staple of portraiture, and of Neel's portraiture in particular. Where her subjects look, how they look, what their looking looks like. Neel is, above all else, a portraitist of the eye. And yet here is Warhol, himself a painter of portraits, with his eyes shut, eyeless.

What can it mean? Alice Neel was 70 when she painted Warhol this way, a survivor of all kinds of things. In her twenties, she had lost one infant daughter to diphtheria and another to the disapproving family of her Cuban first husband. There were breakdowns, suicide attempts, spells in asylums. Neel's style, too, was a problem. In her show at the Whitechapel Art Gallery, you will see shadows of all sorts of painters – of Edward Hopper, Van Gogh, Cézanne, left-wing muralists such as Diego Rivera, of the German Neue Sachlichkeit school. All are figurative, though, a problem for Neel when Abstract Expressionism took over as the dominant American orthodoxy in the 1940s. Above all this, there was the unremitting pressure of being a woman in the notoriously macho world of New York art. Upstairs in the Whitechapel is a small, aching picture called Fire Escape, painted in 1946. Its subject is again a pair of eyes, in this case Neel's own, gazing out unseen though what look like prison bars, as trapped as an artist by her womanhood as, a couple of blocks away, was Louise Bourgeois.

And Warhol? In the late 1960s and already a pensioner, Neel suddenly hit the big time. In the Fifties, she had struggled to make ends meet. Now, an icon of the Women's Movement, she was taken up by the edgier end of the Manhattan social spectrum.

She painted media plutocrats and their wives, curators, critics such as Meyer Schapiro, poets, other artists. In 1970, she did Kate Millett, author of Sexual Politics, for the cover of Time magazine. Three years later, it was the turn of Linda Nochlin, whose 1971 essay, Why have there been no great women artists?, invented feminist art history more or less from the ground up. Unexpectedly, Neel shows Nochlin as a mother, with her six-year-old daughter, Daisy, sitting next to her on an Empire sofa. Again, it's the eyes that have it: Daisy's are excited, bright, Nochlin's shrewd, appraising and old for their years. Both, you feel, are reflections of Neel herself, of her incessantly youthful eye, the weariness of age.

And here, around the corner, is Andy Warhol with his eyes shut. I'm still puzzled about what kind of image Neel's picture is. Every portrait is a contract, a tacit agreement between artist and sitter. As we all know, it is annoyingly easy to take a photograph with the subject's eyes closed; Warhol was an inveterate snapper of other people. A painting, though, calls for complicity. Did Neel ask him to sit with his eyes shut, or was this merely one pose from many in their sitting? In either case, why did Neel, the supreme portraitist of the eye, choose to show her subject in this way?

Around another corner is an arresting canvas, called TB Harlem and painted 35 years before. It shows a man, poor and ill, lying in bed. Like Warhol, he has a wound in his side; in this case, the result of surgery to remove a tubercular rib. There, similarities between the two pictures end.

In 1940, when she made TB Harlem, Neel was still an overtly political painter, producing images of square-jawed communists and hollow-eyed workers. The subject of this picture is a left-wing martyr, his wounds inflicted by his poverty. Warhol's, by contrast, were the result of being shot by Valerie Solanas, a feminist writer and one of the Factory set. Solanas, in her testimony, gave as her reason for shooting the artist the control he had exerted over her, his inability to see his subjects as anything more than commodities. His work, his way of looking, was as far from Alice Neel's as it is possible to be. Which leaves us with a question, the answer to which I still don't know. The eyes of Neel's portraits are also her own eyes, signs at once of seeing and of being seen. Does she show Warhol as eyeless because he couldn't look at her, or at himself, or because she can hardly bring herself to look at him?

To 17 Sep (0207-522 7888)

Next Week:

Charles Darwent sees the Royal Academy's Sargent and the Sea, watered-down Impressionism with a pinch of American salt