“Sing Sing” follows the well-trodden path of a motley group of amateur actors as they come together to rehearse and put on a play in front of their peers. It’s different this time, though, because everyone is a captive audience. The movie is set inside a maximum security prison in New York state, highlighting a real-life rehabilitation program that works to offer inmates an artistic outlet and featuring a cast that includes many formerly incarcerated actors.

This is a premise that could turn horrifically treacly or maudlin. But Greg Kwedar — who directs and co-writes with Clint Bentley — has a firm, no-nonsense but emotional hand, even if he uses a few too many razor wire-through-the-window shots. It’s a cinematic high-five to all arts programs behind bars and, in particular, the power of theater. If you are a cynic, “Sing Sing” may be an elaborate infomercial for its Rehabilitation Through the Arts program. Even if it is, it’s wonderful. Cynics are not welcome here.

Part of its power is Colman Domingo, who is finally becoming indispensable in Hollywood. He got his flowers in George C. Wolfe’s “Rustin” and now deserves a larger bouquet playing not just a key part of the Sing Sing theater program, but its soul. To see inmates acting — which requires participants to be real, vulnerable and honest — isn’t “something men don’t get to do too often,” says the program’s director, one of the movie’s only free characters, played by a nicely understated Paul Raci.

We first find Domingo as Divine G, a one-time “Fame”-high school actor and playwright, trying to help determine which show they should mount next and who will be onstage. He’s a lot like other actors — a tad vain, self-involved and reverential when it comes to the craft. He is challenged by the appearance of the very dangerous gangster Divine Eye — played fiercely by magnetic former inmate Clarence Maclin — who has a raw poet’s heart underneath all that menace. (“My slings and arrows are on the inside,” he says). Taming him to be emotionally open — or at least not bashing in the skull of someone passing behind him, a prison no-no — will take some nuance and patience.

“Sing Sing” is based on “The Sing Sing Follies,” a 2005 Esquire article by John H. Richardson, as well as personal interviews that Kwedar and Bentley conducted with current and former participants. Kwedar’s camera is often shaky and he sometimes has his actors talk in overlapping dialogue, giving “Sing Sing” a documentary feel. He is sober about the indignities inside, from random violence to endless lines. Surrounding these men is a faceless, pityless system filled with guards routinely tossing cells, stern parole boards and lockdown sirens. The acting program allows individual expression in a world where they are mere numbers in prison green.

Freedom

The movie’s band of actors — now tired of heaviness after having just done Shakespeare’s “A Midsummer Night’s Dream” — ask for a comedy and the director dreams up an insane one, featuring ancient Egyptian mummies, time travel, Old West gunslingers, Freddy Krueger, gladiators and a soliloquy from “Hamlet.” The movie’s most affecting scenes are the ones that follow the inmates doing the craft — tender auditions, reciting their lines while doing chores and working on their characters. Watching them giddy backstage in costume before a show is all of us. “We here to be human again,” says one.

The movie’s script is not content with just an inmates-put-on-a-show premise so it has added some depth — parole board freedom for one in the cast and a sudden death. Sometimes they are clunky touches and you just want to go back to the scenes where the inmates are bonding and bursting with art. “Sing Sing,” after all, is a song about how art can sustain us in even the darkest hours.

Clarence “Divine Eye” Maclin is standing inside Sing Sing Correctional Facility for the first time since he was incarcerated here 12 years ago. In this very chapel, he reminisces, he once sold drugs — a backup plan for when the yard was closed. Not many men pine to return to the prisons in which they toiled away years of their life. Maclin, 58, lived inside Sing Sing for 15 years. But on this day, he’s buoyant. “I got a purpose now,” Maclin says.

Maclin was at Sing Sing, the 198-year-old maximum-security prison perched on a hillside overlooking the Hudson 30 miles upriver from New York City, last Thursday for the premiere of the upcoming movie “Sing Sing.” In the film, which opened July 12 in theaters, Colman Domingo stars as an incarcerated man who helps lead a theater program for others at Sing Sing. Together, they find community and catharsis through theater. The program is real: Rehabilitation Through the Arts, or RTA, is a nonprofit founded by Katherine Vockins at Sing Sing in 1996. Many of its former participants make up the cast of “Sing Sing” alongside professional actors like Domingo and Paul Raci. Maclin plays himself – a hard, muscle-bound character whose talent for shake-downs in the yard, it turns out, transfers remarkably well to Shakespeare. “On stage,” Maclin says, “I got permission to do anything.”

As movie premieres go, the one for “Sing Sing” at Sing Sing was about as poignant as it gets. The film was screened above the stage where RTA performed its first show for an audience half civilian, half incarcerated men in navy green jumpsuits. For the formerly incarcerated actors in the film, returning to Sing Sing was an emotional homecoming. They brought a message of hope and healing that they, themselves, are still trying to live up to.

Plaques outside the walls of Sing Sing — a high-walled citadel of incarceration beside which trains carrying commuters pass regularly — tout its rich history. This is where phrases long ubiquitous in movies — “Up the river,” “the Big House” — come from. Historically, Sing Sing — where, among many others, Julius and Ethel Rosenberg were executed — has loomed in the public imagination more as a symbol of harsh, Victorian age-style punishment than soulful rehabilitation. (By Mark Kennedy - AP)