The panel discussion was supposed to start at 5:45 p.m. Monday, but the principals were still trickling in at 6, and the presentation didn't get under way until well past its announced start time.

Nothing new there. They were rock n' roll artists, after all --hardly a group known for its punctuality.

Wilson Library on Monday opened one of its more unusual exhibits -- music posters by Casey Burns and Ron Liberti -- with one of its more unusual presentations: a short discussion with the artists and Cat's Cradle owner Frank Heath, followed by a rock concert, with performances by Billy Sugarfix, Lud and Regina Hexaphone.

It's doubful that the normally sedate Pleasants Family Assembly Room, home to many lectures, panels and presentations, has ever been quite so loud.

The exhibit, on display in the Manuscripts Department on Wilson Library through May 31, features posters Burns and Liberti -- both of whom are also musicians -- created for shows at local clubs, most of them at the Cat's Cradle.

Some 30 posters are in the exhibit, including ones for shows by Tift Merritt, Southern Culture on the Skids, Gang of Four, the Rosebuds, Sonic Youth and more.

Over the years, Burns and Liberti have developed distinctive styles, and their artwork reflects in visual images the independent rock music scene in Chapel Hill and Carrboro during the last 15 years.

"Whenever Ron sees that a band he loves is coming, he comes running to ask whether he can do the poster for them," Heath said. "Somehow he gets in the door."

Both Burns and Liberti got their start in the poster business by playing music. They each started making flyers to advertise gigs by their own bands, and then branched out to begin doing flyers for other groups.

Liberti, originally from Passaic, N.J., moved to Chapel Hill in 1991; Burns, from Hendersonville, came here in 1993 to attend UNC. Before they met, they were independently designing posters and other materials for local shows.

"I was putting up flyers for a show by some friends from Athens one day and I walked into the Hardback Cafe, where Ron was working," said Burns, who now lives in Portland, Ore. "He said, 'Hey, man, have you got another one of those?' I thought, hey, here's another guy who likes flyers."

At the time Liberti was writing a "Poster of the Month" column in a local magazine. He recalled writing one about one of Burns' posters.

"I judged them on a scale of one to five staples," he said. "Casey's got, what, four and a half staples?"

"I like to round up," Burns said.

The two artists work in different styles -- Burns does more figurative illustration, Liberti works more with collage techniques --but both are after the same thing: to use images, words and numbers to convey visually some sense of a particular band's music.

"If I'm not familiar with the band, I'll listen to some of their records to get a feel for what they're trying to communicate," Burns said. "Then I try to come up with a way to convey the same thing on a poster."

The club owners and musicians are almost always happy with the results -- almost. Liberti recalled a poster he did for a show at the Cradle by Frank Black, frontman for the Pixies, that Heath was less than thrilled with.

"Frank Black looks a little like Frankenstein, so I went with that and sort of created this Frank Black-as-Frankenstein thing," Liberti said. "But before he got there, Frank ran around taking down all the posters. He said, in his very diplomatic way, 'Um, Ron, I just want to let you know I feel a little awkward about portraying him as a monster.'"

Heath cleared the poster with Black's road manager before putting it back up.

"He just wanted to play it safe," Liberti said. "Frank Black wound up liking the poster just fine."

Reflecting various styles of music, a number of Burns' and Liberti's posters are on the edgy side. Skulls and fangs, for example, aren't uncommon; one poster in the exhibit, for a show by the Melvins, depicts a man with one eyeball that has come explosively loose from its moorings.

All of that is fine with Heath, as long as the artists don't neglect to include certain pragmatic information, in legible text.

"I appreciate a poster people can read from down the street," he said, "with the name of the band, the date and the club."