America's first international art star -- Benjamin West of London -- was an affable and handsome Pennsylvania Quaker whose astonishing career demolishes the law that nice guys finish last.

He was generous, sweet-tempered and wholly unaffected, yet lived a life of triumph. Born poor in 1738, he died rich in 1820. Though a democrat and patriot, he was counted as a friend by King George III of England -- and the two men remained confidants even while their native lands were bitterly at war. London's polished painters might have been expected to spurn West as an upstart, yet they chose him as their leader. In 1792, the innkeeper's son from Springfield, Pa., was unanimously elected president of the Royal Academy -- a position that he held for nearly 30 years.

Though West was once esteemed as "the second Raphael," that claim today seems laughable. Time has been unkind: West's scenes of gore and battle, his histrionic histories, angels and dragons, seem overwrought to the modern eye. His dying heroes seem to sing arias as they fall. But if he was no master, he was among the most successful teachers of his age.

"Benjamin West and His American Students," the intriguing 110-piece loan show that goes on view today at the National Portrait Gallery, includes among its stars Gilbert Stuart, Charles Willson Peale, John Trumbull, Washington Allston, Robert Fulton (the inventor of the steamboat), Samuel F.B. Morse (the inventor of the telegraph) -- and Benjamin West, who taught them all.

He lent them money, fed them, improved their brushwork and their manners, found them rooms and patrons and instructed them without fee. Gilbert Stuart thought West "the wisest man" he'd ever met. "He had no secrets or mysteries," remembered William Dunlap, another of West's pupils, "he told all he knew."

West never forced his students to imitate his art. He encouraged them to study the work of other painters, to improve their techniques and to follow their own paths. "Work, night and day," he told them, "draw from the antique, paint from nature. Study the masters." West made them better painters. The best of them arrived in London as provincials and departed as sophisticates.

The exhibition, with its many little one-man shows, illustrates the peculiarly American characteristics -- straightforwardness, innocence, affection for hard edges -- that these artists brought to Europe. Its before-and-after theme also summons our attention to that love of high art, that reverence for tradition, with which they returned.

Gilbert Stuart left for London in 1775. The first painting of his on view, a portrait of Dr. Benjamin Waterhouse, is dull and tightly painted. Its contrasts are too harsh. It seems to be the work of better-than-average Colonial limner. But as soon as he meets West, with whom he spent five years, his art begins to change. West, imitating Rubens, had painted a self-portrait in a dark fur cap. Learning from his teacher, Stuart does the same. Stuart then moves into the styles of Gainsborough and Romney. For West made it his business to introduce his pupils to the best new English art.

West's own influence is clearly seen in the dramatic Bible scenes and histories painted by his pupils.

The hopeful young Americans who worked with West in London left behind a land in which fine works of art were rare -- and only portraiture was prized. aJohn Singleton Copley, who sought out West in London (but was not one of his pupils) had hard words for Boston. "Was it not for preserving the resemblance of particular persons, painting would not be known in the place. The people generally regard it no more than any other useful trade . . . like that of a carpenter [or] tailor." West set higher goals. Paintings, he believed, should be noble objects, soaked in lofty sentiment and high moral value. If they told juicy stories and entertained the viewer -- well, so much the better.

West, in his finest pictures here -- "The Cave of Despair" or "Death on a Pale Horse" -- appears to share as much with Disney as with Raphael. West, the history painter to the king, filled his most successful paintings with skeletons and warriors, bats, snakes and explosions -- and his students took the hint. Ships burst into flame and screaming sailors writhe and drown in Mather Brown's "The Battle of the Nile." Both Morse's "Dying Hercules" and Charles Robert Leslie's "The Murder of Rutland by Lord Clifford" are paintings of high drama. In Thomas Spence Duche's portrait of Rev. Samuel Seabury, one can almost hear the howling wind puffing up the minister's huge sleeves.

On the day West died in 1820, his old servant was heard asking, "Where will they go now?" Later generations of young artists from America would go to France, first, where they would immerse themselves in the Greek revival. Later they would head for Rome, or for the academies of Dusseldorf and Munich. In the first years of this century, those searching for the new would set their sights on Paris. West had set a trend.

The show was organized by Dorinda Evans, who wrote the 200-page catalogue.

The exhibit will travel to the Pennsylvania Academy of the Fine Arts after closing here Jan. 4.