THE photographer Vik Muniz often says that while he considers himself an American artist, his use of imagery owes everything to Brazil, where he was born and raised.

“I’m a product of a military dictatorship,” he said recently at his New York gallery, Sikkema Jenkins & Company. “Under a dictatorship, you cannot trust information or dispense it freely because of censorship. So Brazilians become very flexible in the use of metaphors. They learn to communicate with double meanings.”

Certainly his photographs are filled with the visual equivalent of double entendres. At first each seems to present a familiar image or artwork. But examine the picture up close, and it turns out to be made from surprising mediums, like Bosco syrup, which Mr. Muniz once dribbled across vellum to recreate Hans Namuth’s photograph of Jackson Pollock making a drip painting; peanut butter and jelly, from which he molded a Warholesque “Double Mona Lisa”; or plastic toy soldiers, which he used to recast a Civil War photograph of a boyish-looking private.

This penchant for multilayered imagery may be one reason Mr. Muniz, a puckish 48-year-old who has been an art world fixture for more than a decade, is now a celebrity in Brazil. In the last two years his traveling retrospective, simply called “Vik,” has been in five cities there, achieving record attendance. He has also funneled much time and money into nonprofits (which have flourished in Brazil’s democracy), most of which are located in Rio de Janeiro, and intended to provide education and job training for street children.

At the time of our interview, the voluble, charismatic Mr. Muniz had just flown in overnight from the São Paulo Biennale on a 48-hour tour of New York, where he oversaw the renovation of the Brooklyn studio where he lives part time (when not in Rio), checked in with his dealer and was an M.C. at a benefit gala for the nonprofit Brazil Foundation at the Metropolitan Museum of Art. There he was named a Unesco Goodwill Ambassador.

Now, as the star of “Waste Land,“ a touching documentary that opens on Friday after winning numerous film festival awards, he seems on the verge of reaching a broad audience in this country too.

The film, directed by Lucy Walker (“Blindsight,” “Countdown to Zero”), tracks the development of a 2008 series of monumental photographic portraits made from trash. Called “Pictures of Garbage,” they were created by Mr. Muniz in collaboration with the garbage pickers of Jardim Gramacho, a 321-acre open-air dump just outside Rio that is one of the largest landfills in Latin America.

This informal workforce — or catadores, as they are known — are the reason Brazil, with only a few municipal recycling programs, manages to reclaim a huge percentage of its trash, said Sonia Dias, the waste-picker specialist for Wiego, a global policy research group. This summer Brazil passed a law to eradicate open dumps and integrate the catadores into the recycling industry. Yet the catadores are still an underclass. The film tells the story of Mr. Muniz’s efforts to help those at Jardim Gramacho take charge of their lives, while giving them a new perspective on the world through art.

It begins in Mr. Muniz’s Brooklyn home. “I’m at this point in my career where I’m trying to step away from the realm of fine arts,” he says to the camera, “because I think it’s a very exclusive, very restrictive place to be. What I want to be able to do is to change the lives of people with the same materials they deal with every day.”

He informs his wife at the time, the artist Janaina Tschäpe, that he intends to spend two years at Gramacho, working with the catadores. Mr. Muniz is then seen amid Gramacho’s majestic mountains of trash meeting the catadores with Fabio Ghivelder. “I grew up poor,” Mr. Muniz says. “Now I’ve reached the point where I want to give back.”

The catadores in the film soon reveal themselves to be as personality-packed as Mr. Muniz. They include Tião Santos, president of the workers’ cooperative Association of Collectors of the Metropolitan Landfill of Jardim Gramacho; the scholarly Zumbi, who has educated himself by reading discarded books; Suellem, a teenage mother who has worked at Gramacho and lived in its shantytown since her childhood; and Magna, who became a catador when she and her husband fell on hard times. Though their work may be grim and dangerous, many of them seem to have a crystal clear idea of its environmental worth. And, as Magna says, “It’s better than turning tricks at Copacabana.”