If you were a teenager in the 1960s, then you probably believe Ken Sanders was a witness to history the night he first saw Janis Joplin.

It was Sept. 30, 1967, in the Terrace Ballroom — in downtown Salt Lake City. Sanders still sounds amazed when he talks about it.

He didn't know who Joplin was. He'd come to see her band, Big Brother and The Holding Company, because in those days, he says, that's just what you did.

"The Terrace Ballroom was our Avalon, our Fillmore," Sanders says. "You just went there, if you were into rock music. Sometimes you'd know the bands. Sometimes you didn't. You went to check them out. It was a social scene."

Joplin was unlike anything he'd heard before. "The band played an opening set, and this hippie chick came stumbling out onstage," he recalls. She clutched a bottle. Much later, Sanders would learn the bottle held Southern Comfort bourbon.

Then Joplin started to sing, to rasp out her songs. Sanders says he wasn't the only one in the audience dying to know her name. "She was electrifying. It was like she was channeling Bessie Smith or something."

Sanders will talk about Joplin on Sept. 16, at the Rio Grande Depot. He'll give a lecture and show slides of his posters of dozens of rock concerts held in Utah during the 1960s and '70s. "One of my talking points will be the accident of geography."

An accident of geography put Salt Lake City a day's drive from San Francisco, and thus the perfect stopping point for a Bay area rock band on its way east.

Sanders owns a poster advertising the 1967 concert at the Terrace. It doesn't mention Joplin. In wacky lettering, the poster merely says "Big Brother and the Holding Company." Soon after, Joplin became the band's headliner. "And four years later, she was dead," Sanders says. He will remind his audience, on Friday night, that there were also a lot of Utahns who were casualties of drugs and alcohol in those days.

Sanders owns more than 200 locally produced concert posters. Some, like his Grateful Dead poster, are autographed by band members. He likes to reminisce about the Rolling Stones coming to Lagoon in 1966. About the Doors, Jefferson Airplane, Pink Floyd, Jimi Hendrix coming to Salt Lake City. About the 1969 Grateful Dead SDS (Students for a Democratic Society) Ball. He likes to talk about the Terrace and the Fairground Coliseum and about the artists who designed the posters for all these groups.

He likes to talk about what makes the Utah poster art unique. "The San Francisco posters are a well-known American art form," he says. But local artists like Neil Passey, Rob Brown, Kenvin Lyman and Richard Taylor developed their own look. And their posters are rarer.