WILLIAM EDWARD WEST and Charles Harding are two more of those fine, forgotten early American painters the National Portrait Gallery happily keeps reminding us about.

Both largely self-taught portraitists, West (1788-1857) and Harding (1792-1866) became enormously successful. Between them they painted most of the famous Americans of their day, along with not a few British notables. West was, for instance, commissioned to paint Lord Byron at the height of the poet's fame; and Harding for a time overshadowed Gilbert Stuart.

Their reputations faded early, even though, as can be plainly seen in companion exhibits opening this Friday at the Portrait Gallery, West and Harding were artists of skill, vision and courage. And whatever their weaknesses, each in his own way was a master of illuminating character.

Although their careers as itinerant painters were contemporary and closely parallel, their paths seldom crossed. West was a Kentuckian who was so sure of his talent he spent more time partying than painting, staying for long periods with the families -- or clans -- whose portraits he was taking. When not abroad, he generally worked the South, particularly the great plantations along the lower Mississippi.

"One of the reasons West is so little known is that many of his portraits are closely held by the descendants of his sitters," says Estill Curtis Pennington, whose researches into the life and work of his fellow Kentuckian have become an obsession that has some of the elements of a gothic novel. Pennington, director of the Lauren Rogers Museum of Art in Laurel, Mississippi, used everything from gentle persuasion to a cherry-picker crane to gather the works in this first-ever (!) exhibition of West's work.

He knows the stories behind nearly every painting, and tells them beautifully. When he describes how the wife of Jeff Davis' elder brother snatched her husband's portrait from the flames as Union troops burned their plantation, you see the smoke and feel the heat and smell them damn Yankees. The sadness deepens into irony as you learn that she then died of heart failure, and that the elder Davis was a staunch Unionist.

Chester Harding was a huge, lively backwoodsman from western Massachusetts whose wit and warmth kept his sitters marvelously entertained while he painted them, warts and all. While West may have had somewhat better technique, particularly in his wonderful rendering of eyes, Harding's works have more power: There is a certain unyielding New England flintiness behind his searching and sympathetic examination of his subjects.

Because he worked more rapidly and more steadily than West, Harding left a much larger body of work; he was the one who searched out and painted Daniel Boone, whose explorations opened the way to the "dark and bloody ground" where West was born and raised.

Harding had great self-confidence but few illusions about himself. In his later years he painted less and hunted and fished more, saying he didn't want to diminish his reputation by forcing a faltering hand. Yet his portrait of General Sherman, which Harding finished only weeks before he died, may be the best that ever came from his brush.

WILLIAM EDWARD WEST -- Through June 16 at the National Portrait Gallery. Free lectures by Estill Curtis Pennington at noon on April 18 and 20.

CHESTER HARDING -- Through September 2 at the Portrait Gallery.