Tate Gallery, London
Fifty years ago, in August 1949, Life magazine published a picture of , smoking moodily, under the headline: "Is he the greatest living painter in the United States?" America, not surprisingly, was eager to challenge centuries of European artistic domination, and so was desperate to find a figure who could paint the nation into the history of 20th-century art; and Pollock emerged as the most likely candidate.
Even among New York's finest, it wasn't easy to find a completely American painter: Willem De Kooning was Dutch, Mark Rothko Russian by descent, Barnett Newman Polish, Arshile Gorky Armenian. But had the makings of a genuinely home-grown hero. Born on a ranch in Wyoming in 1912 and famously photographed in full cowboy dress 15 years later, he looked the part - : cowboy, artist, all-American hero.
Even without Life magazine turning him into a centrefold; even without the tales of his drinking and brawling (he once tried to settle an argument with the painter Philip Guston by throwing him out of the window); even without his premature death, drunk, in a car crash in the summer of 1956; even without all this, the Pollock myth was begging to be made. American art was looking for an American legend, and was that legend on a plate.
Enough of the myth. What of the paintings? When they were last shown in this country in any quantity, at the Whitechapel Art Gallery in 1958, the watchwords were "violent", "chaotic", "raw" - words which tied the work back into the life of the hard-man drinker. 50 years on, it's still hard to separate the paintings from what we know of the man - such is his physical presence within them - but the overriding impression at the Tate is one of calm. The best paintings are as energetic and physically exciting as the day they were painted. And yet, the mood of this exhibition is a seductive one with moments of real clarity, especially in the two years from September 1948 (and this really doesn't square with the legend) when Pollock was off the booze completely.
The first thing that becomes clear at the Tate is that the great American hero had a distinctly European start. There are some influences from closer to home: Milton Avery, Thomas Hart Benton, and shades in some early drawings of the influence of the Mexican muralists, but it is Pollock's admiration for Picasso and Joan Mir that looms largest over the opening rooms. Both were exhibited extensively in New York in the late 1930s, and young Jackson borrowed all that he could. And he adapted and he Americanised: casually in the case of Mir - Pollock's Untitled (Blue (Moby Dick)) of the early 1940s is a homage to the Spaniard in all but title - and thoughtfully in the case of Picasso. Picasso was the challenge; an exhibition of his work at the New York Museum of Modern Art in 1940 was, for Pollock, a gauntlet waiting to be picked up.
It was another exhibition at Moma in the following year, "Indian Art of the United States", which provided him with the means. Just as Picasso had been fuelled by the arts of Africa, here was a so-called "primitive" art that Pollock could call his own. Something of the wrapped-around, all-over quality of tribal totems found its way into his work almost immediately, but the lingering and most significant impression was that of the Najavo medicine men making paintings by pouring sand upon the ground. Jackson the cowboy, it seemed, was more of an Indian at heart.
His shift from fledgling Picasso to full-grown Pollock didn't happen in an instant, and the build-up at the Tate is slow and not altogether steady. There are some really bad pictures, and others that now look like landmarks of his early career. Stenographic Figure shows a figure painted in a kind of looping shorthand surrounded by secretarial swirls. It was described by Piet Mondrian in 1943 as "the most interesting work I've seen in America" and convinced Peggy Guggenheim, Pollock's first and most important patron, to take him seriously.
Another work, shown at the Tate (the first time it has been seen in this country), which looks absolutely key to Pollock's development is the 20-foot-long Mural that he painted for Guggenheim's apartment, reputedly in 24 hours at the end of 1943: a giant pattern of green and yellow swirls tied by bending black verticals. It's a painting that goes back 10 years to a little picture, Untitled (Composition with Figures and Banners), the first to use the recurring motif of strong black lines to dissect the swirl in vertical segments, and forward to the works where these lines take on the character of dancing figures.
These are paintings which have to be experienced close up. The scale is crucial: the sense of their being just larger than life, of a man working within and around the picture. It is often said that the "all over" quality means that they have no focal point, though I'm not so sure - the layers come and go, constantly shifting, almost dancing, most often from left to right - and our eye goes with it. One sees this fluidity time and again in these pictures, and most clearly in a work like Summertime of 1948, a famous and familiar image from the Tate's own collection, but shown here in a new light.
The curators have indulged in a piece of intriguing, if prescriptive, hanging, surrounding Summertime with a series of little-known works in which the shapes of figures are sliced from the paint-leaden canvas, revealing dancing silhouettes. These owe something perhaps to Matisse's cut-outs of around the same time, hinged back to the jokier side of surrealism, and not in themselves very interesting. But they turn Summertime into an essentially figurative picture - the dripped and poured black paint becomes a series of dancing figures.
The dripping began in 1943, and by 1948 it was a completely resolved technique. Gradually the denseness and claustrophobia of the first dripped works gave way to a lighter touch, allowing space between the arcs and splashes, forming a way through the layers. Ironically, given that there was always air between the end of his brush or stick or turkey-baster and the canvas, there is a stronger sense in these works of the artist's physical touch than in any other work I can think of. No illustration can begin to do it justice: it is something that has to be experienced to be understood.
Between 1948 and 1950, Pollock's superficially messy technique reached a peak of sophistication. Pictures such as Autumn Rhythm: Number 30 and Lavender Mist are controlled, and even a little beautiful, some would say decorative (Francis Bacon called him "the old lace-maker"). But the lasting impression is that these are still some of the most exciting paintings ever painted. It's no accident that the best of them were painted sober - there's a measured quality, despite the swirls and skeins of paint.
Hans Namuth's film of the artist at work in 1950 confirms this: at times the pace is furious, but more often Pollock moves around, across and within the works in a deliberate, balletic trance. It's quite a performance, and one which turned Pollock into the grandaddy of performance art - action painter extraordinaire - more fuel to fire the myths of painter hero.
Sobriety didn't last. The doctor treating his alcoholism died in a car crash in 1950, and soon after, Pollock was back on the booze. There followed, in 1951, a series of intensely dark and powerful pictures, painted in black enamel on raw canvas. Black had long been the defining colour of the work, but in these late pictures, blackness became the driving energy of the work itself.
By 1952 the technique was taking over. He knew it and (all credit to the man's integrity) he stopped. Two pictures hung in the last room of the Tate's exhibition look like the proof of his final facility. The superbly calligraphic Number 1, 1952 and best of all Blue Poles - a return to the monumental scale and rhythms, and almost even the colours of the 1943 Mural reworked by the master dripper. The patterns of the paint follow the same shapes, the eight vertical lines define the sections - there's nothing accidental about it.
Blue Poles is the closest thing to a mature work, and it's a well-thought- out bit of curating that has made it the end point of the show. Chronologically, that honour should have fallen to an unresolved group of pictures from 1953 and 1954 which show him searching, blindly, for a new direction. Neither the schizophrenic Portrait and a Dream, nor the murky depths of Ocean Greyness, nor the Matisse-inspired Easter and the Totem provide any convincing clues as to what might have happened next.
Blue Poles closed the circle and in a sense there wasn't anywhere left for him to go. Paralysis set in, and Pollock hardly painted at all for the last 2 years of his life. He died, drunk, in his car - just in time to guarantee the legend.
Tate, SW1 (0171 887 8000), to 6 June.