Only two prison arts programs are left in California, and both rely on volunteers and private contributions. The one here is run by the Actors’ Gang, whose artistic director is the actor Tim Robbins. Mr. Robbins has become nearly as familiar a figure at the prison as the warden himself. (The actor, walking through the prison yards, sets off a rustle of recognition among inmates who recall his movie role as a prisoner in “The Shawshank Redemption.”)

Laurie Brooks, the executive director of the William James Association, which runs an acting workshop in San Quentin State Prison, said these programs were first championed in 1979 by Jerry Brown during an earlier term as governor. “We enjoyed this real lush period when there was this boom in prison growth,” Ms. Brooks said. “There really isn’t any state-funded support for arts programs anymore.”

The Actors’ Gang presumably has the fund-raising advantage of its association with Mr. Robbins and its following in Los Angeles, where it staged its own version of “Tartuffe” in the spring. But even it has struggled to raise money. During a break one scorching morning, Ms. Williams asked that this article note that the Actors’ Gang had received a $500 donation in makeup supplies from Mehron Makeup, an act of kindness, she said, that deserved notice.

“People don’t give money because they don’t see us,” she said.

Advocates say these programs have reduced recidivism rates, though there is no conclusive research on that. But prison officials and inmates suggest that the workshops — by forcing inmates to confront emotions and to deal with other inmates they might ignore or fight with outside — can produce fundamental changes in behavior and character.

“No. 1, it breaks down racial barriers,” said Ms. Peters, the former arts facilitator. “It breaks down gang barriers. It’s a safe place for them to come and get away from institutional stresses. And they tend to remain disciplinary-free: If you are busy writing a poem, you can’t be doing drugs.”

Lt. Brian Davis, the public information officer at the Norco prison, who sat in on the sessions, said: “They build self-confidence. I see the inmates starting to work together, and somewhere along the line the fear goes away.”