History's been airbrushed, and the Museum of Natural History is debunking a chief culprit.

"The Vanishing Race and Other Illusions, A New Look At Edward Curtis," an exhibit of 115 original prints and gravures, is surely the museum's most controversial effort to date. Eugene Behlen, chief of exhibits, expects the frankly political approach to attract some visitors, anger others. For more than 60 years, Curtis was critically acclaimed for his multivolume photographic chronicle, The North American Indian. Although the work's artistic merit is holding up and the worth has vastly increased -- a complete set recently sold at Sotheby's for $73,000 -- this show accuses Curtis of fakery in staging his photos and racism in his portrayals of Indians as uncivilized aggressors.

Photographs of "Little Dog (Shunkala)" and "Sitting Owl (Hitdatsa)" show two Indians from different tribes wearing the same outfit. The exhibit reveals the costume was probably a prop from Curtis' traveling wardrobe, used to make his subjects look "Indian." That wasn't his worst offense.

Consider the romantic "On Little Bighorn," in which a cluster of tepees gracefully offset a group of horses cooling in a stream. On close inspection, it's apparent that a wagon has been retouched out of the scene. In other photos, parasols, hats, clocks and suspenders disappeared in the darkroom, skies were darkened and studio backdrops cropped to present threatening-looking natives, "bloodthirsty," according to Curtis. (Those images endure: The museum's aging second-floor displays of warriors brandishing scalps and tomahawks play on the massacre theme.)

The new exhibit stresses that he gave the public the savages they expected, snapping romanticized images to fit the racial stereotype of the turn of the century. Other favorite themes were the Hopi Snake Dance, tribal "types" and the Indian as warrior. In "Ogalala War Party," a group reenacts past military activities for Curtis' camera. He wrote of Indians' "inbred desire for bloodshed," and spent much film on posed battles and posed preparations for battles.

To complement the "warriors" and "scouts," of course, there are "maidens" and "maids." The show zeroes in on the photographer's ethnocentrism, soft-pedaling his sexism and taking pains to put Curtis in his time period. Portraits of bare-chested maids weren't considered pornographic, says the caption, since the Indian women were considered less than human.

The sepia-toned photographs are almost too perfect, which is precisely the point: Images of Indians handed down as factual documents were stilted preconceptions of what the "vanishing race" was like before the whites moved in. There is one photo that saves Curtis from his critics: "Hopi Farmers, Yesterday and Today" depicts two Indians, one in primitive garb, the other in bluejeans. There is no attempt here to hide the changes experienced by the Hopi since their contact with whites.

Christopher Lyman, principal researcher and author of the book based on the exhibit, says "There are bound to be a lot of Indians who don't like this show at all. They believe the stereotype as much as white people."

"THE VANISHING RACE AND OTHER ILLUSIONS: PHOTOGRAPHY BY EDWARD CURTIS, 1900-1930," -- At the Museum of Natural History Thomas Evans Gallery, through April 15. Slide lecture by Christopher Lyman, Friday at noon in Baird Auditorium.