A dramatic exhibition at the Museum of Modern Art in New York in 1966 set the way many Americans still look at the works of the British painter Joseph Mallord William Turner.

By then, Turner had been dead for more than a century -- hardly a conventional subject for a temple of Modern art. But, by concentrating on his later paintings, filled with swirls of color and light and mists and fire and storm, the museum hailed Turner as a godfather of French Impressionism and, even more important, a precursor of American Abstract Expressionism. The show prompted abstract painter Mark Rothko to joke, "That guy Turner learned a lot from me!"

Now, another major exhibition, at the National Gallery of Art in Washington, is trying to put Turner in better perspective. With more than 140 oil paintings and watercolors, the show, titled simply "J.M.W. Turner," is billed as the largest and most extensive exhibition of his works ever assembled in the United States. While not denying his modern credentials, the exhibition shows Turner whole, covering six decades of his art and making clear why critics regard him as one of Britain's finest painters and British poet Alfred Tennyson called him the "Shakespeare of landscape."

The Tate Modern in London, which has the world's largest collection of Turners, lent 85 works for the show. The rest come mainly from American collections.

Turner was born in London in April 1775, the son of William Turner, a barber and wig maker. There was some confusion about the exact date, so the painter, never modest about his talents, later settled on April 23, the same birthday as Shakespeare's.

He was a precocious artist. When he was 12, his father began hanging his signed drawings in the barbershop window for sale. Two years later the boy enrolled in the Royal Academy of Art as a student. His talent was recognized swiftly. Within a year, the Royal Academy exhibited him, showing his meticulous watercolor "The Archbishop's Palace, Lambeth." At 24, he was elected an associate of the Royal Academy. At 26, he was elected a full member, the youngest artist so honored.

Turner was a short, brusque man who never lost his London working-class accent. The American painter Thomas Cole thought he looked like a seafarer; the French painter Eugène Delacroix thought he looked like a farmer. He was a shrewd marketer, setting up his own gallery on Harley Street so he could show whatever he wanted and collectors could buy directly from him. He also made engravings of his best work to augment his income. Although his later style of penetrating light and atmospherics irritated a number of critics, he kept enough customers to amass a fortune.

In Turner's younger days, landscape painting was often belittled. Sir Joshua Reynolds, the president of the Royal Academy, articulated the view of the establishment when he praised history painting as the highest achievement of artists. By this, he meant canvases that glorified scenes from history, mythology, the Bible and literature. Landscape occupied a lower place in the hierarchy of art, but Turner was determined to elevate its standing, both by the sheer brilliance of his work and by melding landscapes with the subjects of history painting.

In "Snow Storm: Hannibal and His Army Crossing the Alps" (1812), an early masterpiece being shown in the United States for the first time, Turner combined landscape and history with the notion, then in fashion in Britain, of the Sublime. Turner was influenced by the English philosopher Edmund Burke, who believed that the depiction of overwhelming and terrifying scenes of nature in a painting would instill in a viewer a growing sense of experiencing sublime greatness. Turner's painting shows the army of Hannibal, the general of the North African city-state of Carthage, crossing the Alps in his ill-fated attempt to defeat Rome in the 3rd century BC. The army with its elephants can barely be seen, for it is overwhelmed by the mists swirling around the mountains and by the brightness of the impending snowstorm.

Paintings such as these attracted the attention and admiration of great American landscape painters including Cole and Frederic Edwin Church. Church's work, in fact, was so influenced by the Englishman that a New York critic, looking at Church's latest painting in 1856, wrote, "Have we a Turner among us?"

The current exhibition emphasizes one of Turner's lesser-known traits: His heroic paintings tended to depict as much suffering as heroism. "The Battle of Trafalgar, 21 October 1805" (1823-24) is his largest painting and the only one to hang in a royal palace. King George IV commissioned it to commemorate the British defeat of the French and Spanish fleets in the Napoleonic Wars. Rather than highlight a grand victory, or even the death of the heroic admiral Horatio Nelson, Turner dwelt on the desperate and suffering seamen clinging to lifeboats. This provoked so many complaints that the king removed it from St. James Palace after five years and sent it to a hospital.

In his later years, Turner began to focus more on the atmosphere that infused a scene rather than the scene itself. He became infatuated with light and color as he dealt with sunlight, fire, mist, wind and storms. The British painter John Constable said that Turner "seems to paint with tinted steam, so evanescent, and so airy."

The change in approach troubled some former admirers. Cole, once influenced by Turner, now called him "the prince of evil spirits" and claimed "his present pictures are the strangest things imaginable." The Spectator magazine belittled the new paintings as "mere freaks of chromomania." But Turner was defended by the young John Ruskin, who would become the most influential British art critic of the 19th century and who did all he could to enshrine Turner as the greatest landscape painter in the history of art.

Polarizing the critics

"REGULUS" (first painted in 1828 and reworked in 1837) demonstrates what baffled Turner's detractors and excited his champions. The painting is based on the story of the Roman general Marcus Atilius Regulus, who was captured by the Carthaginians in the 3rd century BC. According to legend, the captors cut off his eyelids, shunted him to a dark cellar, then carried him to face the searing sun.

From afar, the canvas looks as if it has been cut in two by a swath of white-yellow light. On closer examination, a viewer sees the port of Carthage engulfed by powerful and brilliant sunlight. It is the kind of sunlight that would overwhelm and pierce the unprotected eyes of someone like Regulus who has just emerged from darkness. Regulus himself is barely discernible, a tiny figure among many others on the portico of a palace.

Turner repeated this pattern often. In his two celebrated paintings of 1835 that are each titled "The Burning of the House of Lords and Commons, 16th October 1834," Turner does not focus on the Parliament buildings as much as on the reds, yellows and blacks of the flames as they leap against the sky and reflect in the Thames.

Sometimes his fascination for color and theories of color perception is so powerful that the canvas looks abstract. That is true in "Light and Color (Goethe's Theory) -- The Morning after the Deluge -- Moses Writing the Book of Genesis" (1843). The painting is a mass of swirling brown-and-yellow mist and cloud. But it is not only an exercise in the color theories of the German writer Johann Wolfgang von Goethe. As the title makes clear, the small figure in the center is Moses, and the swirling mass is the Earth after the great biblical flood.

When Turner died in 1851 at age 76, he left behind more than 100 unfinished canvases. These have the hazy obscurity that encouraged 20th century critics to marvel at his abstract modernity. The 1966 Museum of Modern Art show, in fact, was devoted mainly to the unfinished work.

But Turner would never have regarded himself as an abstract painter. He liked subject matter and long-winded titles for his paintings. The current exhibition sets aside a small room at the end for less than a dozen of the unfinished paintings, giving us a more realistic understanding of their place in Turner's long career.