PASADENA, Calif. — FX describes its new reality/documentary series "Black. White." as a "social experiment" in race relations.

Judging by the participants, it wasn't altogether a successful experiment.

"Black. White." which premieres tonight at 11 on FX, took an African-American family (Brian, Renee and Nick Sparks) and used makeup to make them appear white; and a white family (Bruno Marcutelli and Carmen and Rose Wurgel) and made them appear black. The families shared a house during the six-week experiment meant to foster racial understanding.

"If people are talking about race in America, whatever they might be saying, then the show will have accomplished something really important," said executive producer R.J. Cutler. "Race doesn't get discussed nearly as much as it should.

"The struggle for white people to see the world through African-American eyes, for African-Americans to see the world through white eyes, is a really strong one," Cutler said. "The fact that there are really, really strong divisions in this country that don't get talked about and thought about."

Each of the participants got to experience life as a member of another race, and some of those experiences were astonishing — like the young man who said he'd been taught to wash his hands after touching an African-American. But the real conflict came between the participants themselves.

The Marcutelli/Wurgel's trumpet how progressive and liberal they are, yet some of their own racist attitudes show through. And the Sparks' aren't overly tolerant, either.

"One of the things that we wanted to do in the show was explore kind of a broad spectrum of points of view on race, not just kind of ignorant points of view on race but people who saw themselves as open-minded and open-hearted," Cutler said. "And in a way you could say it's as much a critique of progressive viewpoints and liberal viewpoints as it is of anything else."

Months after the six-week experiment ended, the tension between the families was palpable when they appeared before TV critics — Brian Sparks and Marcutelli were clenching their jaws and avoiding eye contact.

"I don't think one transformation or six weeks can accurately show what I go through day to day," Brian Sparks said. "You can get a little taste. You can get an hour or one episode or one incident of how I feel in my every day.

"Bruno said plenty of times that I go out looking for racism. I don't have to look for it. It finds me."

Numerous times Marcutelli insisted that what Sparks maintained was racism was not.