From the ballads sung by convicts in Australian penal colonies to "Folsom Prison Blues," song has been a means for incarcerated people to express their feelings about being locked up.

Visual artist Erik Ruin and vocalist Gelsey Bell explore those thoughts and emotions in Prisoner's Song, which they'll perform at the Rotunda on Friday.

The show, directed by Rick Burkhardt, uses Ruin's meticulously cut shadow puppets, which often resemble intricate woodcut images, and other projections to accompany a song cycle drawing on traditional folk ballads, poetry, archival sources, and audio interviews Ruin conducted with people who have spent time in prison.

"These stories alternate between beautiful, moving spiritual discourse, a lot of really deep wisdom, and really intense descriptions of violence," Ruin says. "I'm really interested, though not in any religious sense, in asking, what is the soul? What is the irreducible part of a human, and how does that expand or contract given their environs?"

A 2015 New York Times review of Prisoner's Song said, "There was a deceptive simplicity to much of the performance that managed to evoke the restrictive and impoverished reality of incarceration even as it paid tribute to the resilience, ingenuity, and poetry that can transcend it."

Ruin got involved with prison activism as a teenager in the Detroit area through a program providing books to prisoners - work he continues to support in Philadelphia through the nonprofit organization Books Through Bars. "I felt like these people who I was corresponding with were deeply lonely and finding solace in books," he recalls. "I was an alienated youth. I'm not going to pretend that my feelings were the same, but they helped me understand. This was a human experience that spoke to my heart in a very direct way."

He began conducting interviews with prisoners in 2011 for a project dealing with the idea of solitary confinement that was never fully realized. He felt an ongoing responsibility to share those stories, though, and was inspired by a recording of a 19th-century folk ballad to create Prisoner's Song. Not long after, he met Bell, a versatile vocalist whose work runs the gamut from singer-songwriter art-pop to musical theater to experimental music.

Bell worked closely with Ruin to create the sound track for the show, which incorporates historic ballads alongside more avant-garde music, creating abstract vocal noises to accompany archival records of prisoners' belongings or swathing first-person accounts in musical atmospherics.

"Folk music is often thought of as being an authentic music, but I'm not coming from an authentic place because I've never been incarcerated," Bell says. "But these songs feel like an archive of that experience in the same way that the words of people who have been in prison are archival. I think of music as carrying that history, and folk song is a place where it can be found."

Ruin discovered shadow puppetry as a young fan of punk rock when a bedsheet stretched across a doorway could serve as an improvised screen between bands at house concerts. His art and activism work traveled largely divergent paths, but Prisoner's Song is one way in which he's starting to reconcile the two. Friday's performance is free, but donations will be accepted at the door for Reconstruction Inc., a local organization that works with ex-offenders to influence community leaders and effect reform of the criminal justice system.

"I don't consider Prisoner's Song an activist piece, per se," Ruin says. "But if it were to help destigmatize prisoners or encourage people to look at our out-of-control prison industrial complex or mass incarceration, that would be great."

Prisoner's Song, 8 p.m. Friday at the Rotunda, 4014 Walnut St. Free, donations accepted. bowerbird.org.