CINCINNATI, SEPT. 28 -- Prosector Frank Prouty opened the Mapplethorpe obscenity trial today by urging jurors to "draw the line" in the first obscenity case against an art gallery, while the defense stressed that the gallery's only goal in bringing the controversial exhibit here was to enhance the community's cultural life.

Arguing the state's case against the Contemporary Arts Center and its director, Dennis Barrie, Prouty focused on seven of the 175 photographs included in the Robert Mapplethorpe retrospective.

"The state's case is in some respects very simple," Prouty told the jury of four men and four women. "... You're going to ask, 'Shouldn't we hear something more?' ... The pictures are the state's case."

Five of the photographs in question depict homosexual and sadomasochistic activity. Two are portraits of children whose genitals are visible. The five pictures were the basis of obscenity charges; the portraits were cited in an indictment charging violations of a state law prohibiting the possession of materials depicting minors in a state of nudity.

Prouty said Barrie and other museum officials "essentially knew what they were doing" when they brought the Mapplethorpe exhibit to the arts center. "Any or all" of the five sadomasochistic pictures are obscene, he charged.

During the previous four days, the defense repeatedly asked prospective jurors whether they believed a portrait of a child whose genitals are exposed could be "morally innocent." In his opening statement, Prouty told the jury, "Look at the pictures. See if that's moral innocence.

"You're probably thinking, 'Obscenity has been around a long time,' " Prouty continued. But he told the jury that this case is unique. "There has never been a museum or art gallery charged with the display of obscenity," he said. "... In other words, you as the jury can take this opportunity to decide, where do you draw the line?"

Prouty admonished jurors to apply state law even if they disagree with it. "Desirability of the law is not an issue," he said. "We're beyond that. We're beyond what your feelings are, what your views are."

Speaking for the arts center, attorney Marc Mezibov countered that "this case is not about photographs, it's about people." Mezibov stated repeatedly that the case involves "people who live in and concern themselves with the betterment of this community." He stressed that the gallery is not run for profit and that many who work there are volunteers.

The arts center voluntarily restricted attendance at the Mapplethorpe exhibit to those over 18 and went to court before it opened in April to seek an advisory opinion on whether the works might be considered in violation of state law, Mezibov said. The court refused to act on that request and "within 12 hours, the arts center was indicted," he recalled.

Arguing for arts center Director Barrie, attorney Louis Sirkin said his client took advantage of a chance "to bring the controversial works of a brilliant photographer" to the city.

"This photographer not only did beautiful pictures, but pictures that were not so beautiful," Sirkin said. The retrospective is like a biography, he continued. In this case, the exhibit was intended to teach "some of the inner workings of the man and some of the torture that perhaps he suffered."

Sirkin stressed that the exhibit was intended to serve legitimate artistic and historic purposes -- key components in the Supreme Court's test for establishing whether materials are protected by the First Amendment.

"I don't know how anybody could, with a straight face and good conscience, say that Dennis Barrie did not ... believe that this exhibit had serious value both for its artistic and technical aspects but also for its political aspects," Sirkin said.

"It showed us a world that did exist... . It showed a period of American history in the 1970s which we may never have again, and perhaps we should never have again."

He continued, "Art is not always pleasing to our eyes. Art is to tell us something about ourselves."

Just before the opening arguments, jurors were driven by van a few blocks to the Contemporary Arts Center. They walked through the atrium, escorted by bailiffs and trailed by reporters and television camera crews. They were brought into the gallery's foyer and permitted to remain there for less than 20 seconds before being whisked back to court.

The prosecution had opposed the field trip, but Judge David Albanese held that the jury could view the scene of the alleged crime. The judge admonished the jurors not to look at the current exhibit, which is a show of photographs by Mike and Doug Starn. But one small work with a double image of Mona Lisa was hanging in the airy, white-walled foyer.

After opening statements, the prosecution introduced its first two witnesses, both officers from the Cincinnati police department's vice squad. Prouty asked the first officer to describe the seven photographs in question.

The officer testified that the five allegedly obscene pictures were part of Mapplethorpe's X,Y,Z portfolio, which was exhibited at the gallery under glass in a tilted display table. He also testified that the artist's written explanation of the works was framed next to the table but said he couldn't remember the contents of that explanation.

Mezibov asked the officer to read the statement of purpose from the gallery's articles of incorporation. The officer read that the purpose was "to add to the cultural and educational advancement of the people of Cincinnati."

Both officers testified that they had first seen the photographs on April 2 -- at the invitation of gallery officials -- five days before the opening of the show. The gallery's curator took them on a tour and tried to explain the works, they said.

The second officer said an investigation was opened in response to calls and letters from citizens concerned about the show. He acknowledged that those complaints came in before the show opened.

So far, the judge has ruled that the jury may consider only the seven photographs in question. But the defense lawyers elicited testimony from the officers that the show was extensive and included many photographs of flowers and portraits.

Sirkin drew a floor plan on an easel to establish that the children's portraits were hung in a different room from the one with the allegedly obscene pictures.

Mezibov asked the first witness to look at a photograph of the display table holding the five allegedly obscene pictures and count the works included in the X,Y,Z portfolio. The officer counted 39.