A museum and curator who exhibited sexually explicit works by controversial photographer Robert Mapplethorpe were acquitted of obscenity Friday, giving the arts community a clear victory in the first such prosecution of a U.S. gallery.

An eight-member Hamilton County Municipal Court jury deliberated about 3 1/2 hours before clearing the Contemporary Art Center and its director, Dennis Barrie, on misdemeanor charges of obscenity and using minors in nudity-oriented material."I think it sends a very important signal that these museums are protected and that they are part of our culture," Barrie said, "and that, as a part of our culture, they should be kept sacred."

Barrie and the gallery were indicted last spring for exhibiting a 175-picture show that included five photographs depicting sadomasochistic homosexual acts and two of children with their genitals exposed.

The prosecution focused on the seven pictures it labeled obscene.

The defense maintained, however, that the exhibition should be considered as a whole and as a representation of Mapplethorpe's life and work.

The trial, the first in which an American museum was prosecuted on obscenity charges, attracted widespread attention as a test case on the issues of artistic freedom, freedom of expression and homosexual rights.

"We've been well within our rights, well within our mission, and doing a great job," said Roger Ach, chairman of the center's board of trustees. "That's exactly what the jury found, and we're very pleased by it."

Ach said he had not been seriously worried that the museum would be convicted.

"We have great faith in the system, and, while we were always concerned when charged with a criminal act, the fact of the matter is, we really did have faith in the system and the people of the city of Cincinnati," he said.

Civil liberties advocates hailed the verdict.

"Today's verdict is a repudiation of the far right's campaign to villify artistic expression in America," said Elliot Mineberg, legal director of the civil rights organization Peo.

"It's a clearcut victory for free expression and the First Amendment," he said. "I'm elated but not surprised by the verdict. It's difficult to imagine how any fair application of the legal standard of obscenity could have produced any other verdict."

In closing arguments Friday morning, prosecutors and defense lawyers had debated the relevance to the case of constitutional protections of freedom of speech.

The defense urged jurors to protect the freedom of artists to create, but prosecutors said obscenity is not constitutionally protected speech and that the case had nothing to do with First Amendment rights.

The verdicts came at the end of the second week of the trial in the courtroom of Municipal Judge David Albanese.

Mapplethorpe died of an AIDS-related illness in March 1989. The exhibit of his photographs drew 8,100 people last spring to the Contemporary Art Center.