It's hard enough to be an artist. It is harder to be a black artist.

In 19th-century America, with slavery still legal or just recently abolished, black artists lived lives of coarse humiliations. Still, some persevered.

Five are represented in "Sharing Traditions: Five Black Artists in Nineteenth-Century America," opening today at the National Museum of American Art. The show is dense with hidden suffering. The artists who produced these gentle works of art -- these bucolic Scottish landscapes, grave portraits, and marble carvings -- did not often paint their blackness. The viewer has to read Lynda Roscoe Hartigan's catalogue to appreciate the insults they endured.

In 1876, Edward Mitchell Bannister (1828-1901) "learned upon reading a newspaper" that "Under the Oaks," a landscape he'd submitted to the Philadelphia Centennial Exposition, had been awarded the first prize:

I hurried to the committee room to make sure the report was true. A great crowd was there ahead of me, and as I jostled through this many resented my presence, some actually commenting within my hearing . . . "Why is this colored person here?"

Finally I succeeded in gaining the attention of the official. He was very insolent . . . "Well, what do you want here anyway? Speak lively . . ."

In an instant my blood was up. The looks that passed between that official and the others were unmistakable in their meaning. To them I was not an artist; simply an inquisitive colored man. Controlling myself, I said with deliberation, "I am interested in the report that 'Under the Oaks' has received a prize. I painted that picture."

The explosion of a bomb could not have created more of a sensation in that room.

Other blacks who turned to art in the 19th century experienced comparable disparagements. When Henry Ossawa Tanner (1859-1937), a student of Thomas Eakins and by far the most accomplished of the painters represented, learned that the Pennsylvania Academy had bought one of his pictures -- and awarded it a medal -- he was advised it would be best if he did not attend the ceremony.

While attending Oberlin College in 1862, half-black, half-Chippewa Edmonia Lewis, the exhibit's only sculptor, was accused of poisoning two housemates by spicing their wine with an aphrodisiac. She was acquitted, but not before being beaten by vigilantes.

Black dancers could dance in the streets for pennies. Black singers and musicians could perform for other blacks with whom they shared a rich part-African tradition. But those who turned to art were forced to depend on white patrons and white schools and, perhaps most important, on the examples of European art.

The five in this show -- Joshua Johnson, a Baltimore portrait painter active between 1796 and 1824, Robert Scott Duncanson, Bannister, Lewis and Tanner -- relied to some degree on white friends and clients (often abolitionists). And each was charged to some degree -- by blacks and whites alike -- with abandoning his race.

When young Duncanson (1821/22-1872) selected a black subject, he was accused of "Uncle Tomitude." When later he turned to painting trees and mountains, Duncanson (whose father was Scottish-Canadian) was charged, by a black relative, with trying to pass for white. The painter responded with hot rage:

Reuben I have lived to the age of 50 years, I have toiled hard . . . You have stated that all my life I have tried to pass for white. Shame on you! Shame!! Shame!! Reuben. My heart has always been with the down-trodden race. There are colored persons in this city that I love and respect, true and dear to me . . . Mark what I say here in black and white I have no color on the brain all I have on the brain is paint.

A listener who hears a Leontyne Price recording has no way of knowing the color of her skin. Something of the sort applies to these pictures. Almost always, the artists address their blackness with such hesitance that the exhibit appears to be, at first glance, just another 19th-century survey.

Joshua Johnson's portraits of Baltimore sea captains, their children and their ladies and their stiff brass-studded sofas recall other portraits by traveling limners. Hartigan writes that Johnson, "like most 19th-century Afro-American artists struggling for remuneration and recognition, largely avoided black subjects."

Duncanson traveled extensively in Scotland, dined on the Isle of Wight with Alfred, Lord Tennyson, and, according to a contemporary, later "repaired to Canada, where his color did not prevent his association with other artists and his entrance into good society." His landscapes are distinguished by their calming other-worldly light. Duncanson, who contended he was "aided by the spirit of one of the great masters," went mad at the end. His life was less calm than his art.

Bannister had an easier time of it. Though he painted a newspaper boy, who may or may not be black, he usually produced Barbizon-style landscapes filled with oaks and cows. Relatively prosperous (his wife ran a hair-dressing salon), he was warmly accepted by his fellow Providence artists. When he died in 1901, the Providence Art Club honored him with a retrospective show, and 11 of the city's white artists placed a granite and bronze monument at the site of his grave.

Lewis, who spent most of her career in Rome, was more willing to take race as her subject. She acknowledged her Indian childhood by carving Hiawatha and "The Old Arrow Maker." In 1867, she took note of Emancipation by modeling "Forever Free," in which a just-freed slave holds his broken chains aloft.

Tanner, the best of these artists, spent much of his life in Paris. His style, which had once suggested Eakins' intense realism, later took on a Symbolist cast. In his Whistleresque "Portrait of the Artist's Mother" (1897), "The Banjo Lesson" (1893) and "Old Couple Looking at a Portrait of Lincoln" (1892-93), he acknowledged his blackness frankly and beautifully. But his last moody religious paintings suggest no single race or place or time.

"Now am I a Negro?" he asked in 1914. "Does not the 3/4 English blood in my veins . . . does not this count for anything? Does the 1/2 or 1/8 of "pure" Negro blood, in my veins, count for all? I believe it, the Negro blood, counts and counts to my advantage -- though it has caused me at times a life of great humiliation and sorrow . . ."

Hartigan's exhibit often hurts the heart. Her show, largely drawn from the permanent collection, is the most useful the museum has mounted in some time. It will be accompanied by a series of lectures, films, concerts and symposia. It closes April 7.