Wham, Blang thank you man

At the Museum of Modern Art in New York, they have just held three focus groups around Roy Lichtenstein's painting Keds, a pair of baseball boots on a yellow, zig-zag background.

One group said that Moma shouldn't have images like that. It made made them think of children who are violent and steal each other's trainers. A second thought it was too jazzy for the museum. The third thought it was fantastic.

The founding father of Pop Art would have been amused to know that he remained controversial at his death. He certainly died one of the most viewed artists in the world.

U2's world tour uses a dazzling animation of his cartoons of seasides and fighter planes, lit up by perpendicular lasers, in their Pop Mart show. France's Bibliotheque Nationale has a massive tapestry designed by him in its main hall.

Unfortunately, you can't see him at London's Tate Gallery. His quintessential comic-strip work Wham! is not currently on show. The Tate has a space reserved for artists who have just died but, at two metres high by four metres wide, Wham! is too big to fit there.

That's a shame for Simon Wilson, the Tate's curator of interpretation. He owes his job to Lichtenstein and Wham! He joined the Tate in 1967, a year after the gallery, to condemnation internally and externally, had purchased Wham!

At his interview, Wilson gave a talk on Wham! while the other candidates gave their talks on Turner and Constable. He demolished the view that Lichtenstein's paintings were merely blown-up comic strips. The comic strips were simply his source material, Wilson said, in the same way that the Suffolk landscapes were Constable's source material. He eased the trustees' fears, telling them that Lichtenstein's comic strips were still lifes, that his art had great formal purity.

Wilson said yesterday: "Lichtenstein took a sketch of a comic strip, treated it as his motif and adapted it into a painting. Because the comic strip images are two-dimensional, they increase the degree of abstraction. He married figuration and abstraction. He simplified and re-drew with a powerful sense of form, evolving a dramatic new synthesis between the demands of abstraction and the urge to represent reality."

Wilson also notes the irony that Lichtenstein's images drew a lot on advertising and came to be continually used by advertising. Numerous advertisers now make graphics with his trademark black Benday dots and also draw in thick, dynamic, sinuous black lines.

But art historians and curators are agreed that at his death Lichtenstein must be seen as more than a pop artist. Susan Ferleger Brades, director of London's Hayward Gallery, which will be showing Keds at its "Objects of Desire" exhibition next week, says: "He was certainly one of the greatest American artists of this century, and I would say he was one of the greatest artists of any nationality. You can look at Keds and think of a pair of baseball boots, you can also think of Van Gogh's potato digger's shoes. Lichtenstein was crucial in the development of Pop Art, but he was very deeply affected by the history of art in his work, which shows a professional knowledge of the work of Seurat, of cubism, of abstract expressionism. He was crucial in transforming the direction of art in public understanding and what art might be.

"At this year's Venice Biennale he showed a relief of a house which came out of the wall. It invaded one's space from the wall and played with one's understanding of perspective, of inside and outside."

Margit Rowell, chief curator of prints and drawings at the Museum of Modern Art in New York, who knew the artist, adds that his work continued to develop and surprise. His most recent exhibition there contained print woodcuts of Japanese landscapes, a far cry from the subject matter of Pop Art, but still in Benday dots and flat applications of colour.

The art critic David Sylvester in an article reprinted in his book About Modern Art wrote, as long ago as 1969: "He evidently relishes the element of certainty, the knowing `exactly what it's going to look like.' And the pictures themselves, hard and precise and cool, look as if they were about certainty. But they aren't about certainty and it's largely the interplay between certainty and uncertainty that makes them go along as they do, being surprising, though they have the look of an art that is not going to sustain its impact."

If Lichtenstein's work transcends the comic strip source aesthetically, it also does so financially, continuing to sell for funny money. Only this summer, Blang! from 1962, showing a tank hit by a cannon blast, sold for pounds 1.7m.