EXHIBITIONS / In the end, size was everything: In his heyday Franz Kline was regarded as the ultimate Abstract Expressionist. But how does he shape up now?

FRANZ KLINE'S retrospective at the Whitechapel Gallery doesn't substantiate its organisers' claim that he was one of the great artists of the 20th century. But it is a timely tribute, offering many useful glimpses of the internal workings of the New York school, and reminding us why Kline's muffled gestures and black-and-white scaffolding were once so exciting.

The huge calligraphy of Kline's canvases, like massively enlarged motifs from some previously hidden book of Zen, stimulated all sorts of talk at the end of the Fifties about 'the furthest edges of aesthetics', and the look of such paintings was widely imitated. In Britain, where very little was known about Kline except through reproduction, he was easily associated with the Beat Generation as well as with Abstract Expressionism. These reproductions (especially influential in later editions of Herbert Read's Concise History of Modern Painting) made Kline's art look so easy to do. A big canvas, a wide brush, some sweeping or gibbet-like marks from a pot of black - and there you were, an avant-garde picture completed in an hour or less.

But nothing in real art is that simple and Kline was right to complain that his paintings involved labour and knowledge. He had a considerable academic background, having spent four years at Boston University and the Boston Art Students League. Kline's young British admirers might have been astonished to learn that he then, in 1935-37, studied art in London at Heatherley's Art School, a most genteel establishment. There, apparently, he was struck by graphic artists such as Blake, Fuseli and Daumier. Back in America in the war years, while his contemporaries were looking at Picasso and the Mexican muralists, Kline thought mostly of the Old Masters. He would sometimes say that Velazquez was behind his most radical-looking art.

Kline's early years are not represented at the Whitechapel, and that's a pity - but on the other hand the show does plunge us into the drama of his mature style. Kline joined Abstract Expressionism just as it reached its height, in 1947-49. His career follows the pattern of the movement as a whole: a long gestation, a short period of high achievement, then decline. Kline's annus mirabilis was probably around 1958, a decade after his friends De Kooning and Pollock came to their first great works. But the pattern is consistent. Kline's quality declined as theirs did, and perhaps for the same reasons.

Something was lost, and the nature of that loss is an unstated subject of the exhibition. Abstract Expressionism - famously done by tough men, boozers and brawlers - was the most fragile of high-modern styles. Collapse was always at the door. There's no doubt that the drinking had something to do with it. Even by modern-art standards, the incidence of alcoholism in the Abstract Expressionists is frightening, and this show's catalogue has photographs of the Cedar Bar that make the artists' hang-out look like somewhere in hell. Then there were the unexpected pressures of sudden fame and riches after years of poverty. In different ways this affected them all. And there were other social causes for the fall of Abstract Expressionism. None the less, what went wrong with the painting was mostly inherent, a consequence of that painting's style.

With Kline, De Kooning, Motherwell, Rothko too, we observe the beginnings of mannerism, as though they came to imitate themselves. At their best, such artists were unique. Each had a purely authentic personal manner. Then the individuality lost its crispness and vision. To see Kline's supreme canvases look at Figure of 1958, Rue of 1959 and especially Cupola of 1958-60. Had Kline lived beyond 1962, when he died of a heart attack at the age of 51, he might have repeated the success of these paintings. But a saddening aspect of the show is that one cannot imagine any repetition being as good, and there are no signs that his style was developing. He died in the prime of life, but also at the time when his art was stuck.

That's because he couldn't deal with colour. One of the mysteries of Abstract Expressionism is the way that its important pictures were so often restricted to black and white. Kline was crucially affected by De Kooning's black pictures of the late Forties and in the years to come he used white space to better effect than any of his contemporaries. None the less he hankered after colour and in picture after picture we see a longing to be a colourist that was never fulfilled. He introduces an oddly Germanic and jewelled palette to paintings that could do without such richness. When he tries all-over colour, as in the paintings dependent on maroon or mauve, the results are embarrassing and even vulgar. I suspect that he was never quite sure of his own taste. This is what kept him from being genuinely innovative.

We value Kline for his scale and the way his heroic-looking pictures turn out to be tentative and troubled. He came to his scale, ie the relationship between the size of his canvas and its internal parts, by chance. That excellent gossip Elaine de Kooning records that in 1949 he visited a friend who was enlarging his own small sketches on a Bell-Opticon. Kline had drawings in his pocket and was astonished when he saw them magnified. Thus was the style born, New York cityscapes becoming those looming and existentialist canvases that belong to Kline alone.

And yet no large Kline painting is totally confident. Admittedly against the evidence, I suggest that he was not truly an abstract artist. There's something about London and Heatherley's that I can't get out of my eye. Kline's abstractions keep reminding me of another American in London, Whistler, and his blurred sights of old Battersea Bridge. Anyway, I wish that Kline had been a more radical painter. His self-association with Velazquez is a bit absurd, but it's true that Kline worried over his surfaces as though he wished to do 'good' painting in the European traditions. This led to tinkering. I wish I could have talked to Kline. By all accounts he was a very nice man - perhaps so nice that nobody told him where he was going wrong.

Whitechapel, E1, 071-377 0107, to 11 Sept.

(Photograph omitted)