"The Salt of the Earth," Wim Wenders’ new documentary about the life and work of the Brazilian photographer Sebastiao Salgado, elegantly inhabits a moral and aesthetic paradox. Salgado’s photographs illuminate some of the worst horrors of the modern world: starvation, war, poverty, displacement. They are also beautiful, dramatic visual artifacts, and their power has a double effect. We are drawn into the contemplation of terrible realities, but at the same time our attention turns to the person bearing witness.

‘THE SALT OF THE EARTH’ Rated: PG-13 Opens Friday at Kahala 8

That is not a fault, either in Salgado’s lifelong project or in Wenders’ consideration of it. It’s just a fact of their common vocation. The filmmaker brings his mellow humanism and globe-trotting curiosity into an appreciative, easygoing dialogue with the photographer’s single-minded vision. They are a well-matched pair. Though Wenders does not appear on camera, he is present as a narrator and a sensibility, recounting his early meetings with Salgado and his collaboration with the photographer’s son Juliano, who is the co-director of the film.

The elder Salgado, for his part, occupies the screen with quiet charisma. Speaking in French and Portuguese — he left Brazil during the military dictatorship and lived for many years in Paris — he modestly tells the story of an adventurous life.

"The Salt of the Earth" begins with the contemplation of pictures taken in and around an enormous, open gold mine, a crowded, infernal place in which Salgado’s camera discovers humanity in its raw, desperate essence.

Those images were part of "Workers: Archaeology of the Industrial Age," a collection published in 1993. Subsequent projects included "Migrations" (2000) and "Sahel: The End of the Road" (2004), whose images of famine and war in Africa are made more wrenching by the photographer’s calm, heartbroken narration of the circumstances in which they were made.

To observe and capture on film the death of another person is a disturbing experience, and also an ethically complicated act. Susan Sontag’s 2003 book "Regarding the Pain of Others" explores the ways that photographs of atrocities can both awaken and dull the conscience, creating a sense of immediacy that is also, inevitably, a measure of the distance between the sufferer and the observer. "The Salt of the Earth," a document of Wenders’ admiration for his subject, largely avoids such complications: a perfectly defensible choice but also something of a lost opportunity.

"The Salt of the Earth" leaves no doubt about Salgado’s talent or decency, and the chance to spend time in his company is a reason for gratitude. And yet his pictures, precisely because they disclose harsh and unwelcome truths, deserve a harder, more robustly critical look.

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