Though he lived and died here, America has slighted the painter Oscar Bluemner (1867-1938). He was a pioneering modernist who helped to build a bridge between the antique and the avant-garde, the Old World and the New. Had he not been German-born, and German through and through, we might today regard him as a hero of American art.

He was daring and eccentric, and liked bright reds so much that in his lighter moments he called himself "the Vermilionaire." But Bluemner died in horror: He placed a fresh sheet on his bed, slashed his throat, and bled to death.

His colors flare and glow. Fifty of his pictures are now on exhibition at the Hirshhorn Museum and Sculpture Garden. They're peculiarly Teutonic, both rigorous and spooky.

He thought Americans ignorant, and did not like the French. The bright colors of French art, he said, were "out of the question" and quite unlike his own, which he claimed were "exactly like" those of the German masters, Cranach, van der Weyden, Durer. Bluemner said his color theories "further developed" Goethe's "with modern scientific methods." None of this went down too well during World War I.

Once, in 1915, while on a sketching trip to the farmlands of New Jersey, the painter and his little son were mistakenly arrested as a pair of German spies. When later in that year Bluemner showed his work at Alfred Stieglitz's Photo-Seccession galleries, one anti-German critic scorned his handsome, harmless, geometric landscapes as "utterly alien to the American idea of democracy." Whatever that might mean.

Bluemner was no radical. His studies at the Hirshhorn show that he built his little pictures as carefully as a watch.

Bluemner was an architect, as his father and his grandfather had both been before him. He came to America in 1892, and soon moved to Chicago where he worked as a designer for the World's Columbian Exposition, that apotheosis of high 19th-century taste. His buildings were eclectic (he liked cupolas and columns), and so were his first drawings of river banks and sailboats. In the early works, there's nothing close to modern in the way he paints.

His colors break free first. In 1910 his river scenes began to have peculiar hues -- his hulls are green and blue; his masts often orange. Bluemner met Stieglitz in 1910, discovered Cezanne one year later, and though in his mid-40s, soon stopped designing buildings to turn to modern art.

He did so as a colorist. His drawing is at all times rigorous and measured. It is his moody color that liberates his art.

Bluemner felt, as Goethe did, that color could suggest joy as well as sorrow. On the back of a color pencil sketch of "Amsterdam Ave. and 152 St." (1911) -- included in this show -- he notes, in German, "make the blue shadows like a corpse, the brown foliage like 'death,' the sky infinite bright, the red sunlight ectasy." Though he flirted for a while with Cubism's conventions (we seem to see his landscapes through faceted glass prisms), formalist concerns could not hold him long. "We stand," he wrote with feeling, "at the beginnings of a great new painting, in which pure color will reign supreme."

His oranges and reds lend his small late landscapes an uncanny power and something of the theater. He saw his landscapes as self-portraits, and the buildings almost seem alive.

In 1926 he moved to South Braintree, Mass., where his last years were not happy ones. He raised the prices for his pictures as his sales slumped; and soon began to drink to much and sleep too little. In 1935 he was struck by a car. His health and eyesight worsened. Bluemner killed himslef in 1938.

There is passion in his pictures, it flares in his deep reds, but seems held in check. Freedom and fastidiousness war in his small paintings. Bluemner sometimes seems to be a cautious Vincent van Gogh or a cramped Georgia O'Keeffe.All the Bluemners at the Hirshhorn belong to that museum. This moving and instructive show was organized by Judith Zilzcer of the Hirshhorn's staff. It closes on March 2.