What better medium than film to extol the liberating artistic potential of photography, especially when the message is delivered as skillfully as it is by Jan Troell in “Everlasting Moments”? There’s a luminous purity to this film that easily sustains its simple story over a length of more than two hours.

Set in the early twentieth century, the tale centers on Maria Larsson (Maria Heiskanen), the long-suffering wife of brutish dockworker Sigfrid (Mikael Persbrandt). Even after she flees with their four children after one of his drunken binges, her dying father tells her she must go back to her husband. One day Maria finds a camera she’d once won in a lottery, and takes it to the local studio to sell. There gentle photographer Sebastian Pedersen (Jesper Christensen) encourages her to try using it instead, and she proves to have a natural instinct for taking exquisite pictures—artless art.

Of course, that hardly brings paradise. Not only do Sigfrid’s infidelities and alcoholism continue, but he gets involved in a strike and the violence it causes, and later he’s called away to serve in the army during World War I. After he returns, the tension between them escalates, especially after Sigfrid wrongly assumes that Maria’s friendship with Pedersen is more than that. His violent reaction earns him a prison term, and the future of the marriage itself is in doubt.

Troell’s approach toward this material is loving and stylistically chaste. He never pushes too hard, even in the ostensible “action” sequences, preferring instead a quiet, almost lapidary tone and an earthen color palette accentuated by the dependence of his camerawork (he shot the film in concert with Mischa Gavrjusjov) on natural light. And he achieves some extraordinary effects, as in a stunning moment when a dirigible passes overhead and casts a moving shadow over the city square where Maria is shooting.

He also secures fine performances. Heiskanen, looking a bit like Imelda Staunton, anchors the film with a portrait of a modest but strong woman conscious of her role in society but also expanding it through her creative work. Persbrandt complements her with a much more extroverted, theatrical turn as the surly but strangely sympathetic Sigfrid, while Christensen’s restraint acts as a perfect alternative to it. The supporting cast, led by Callin Ohrvall as Maja, the couple’s oldest daughter (from whose perspective much of the story is told), etch briefer but incisive characterizations, and superlative work comes from the production team led by Peter Bavman in achieving a real sense of period authenticity. And there’s a fine but sparingly used chamber score by Matti Bye, which adds color without becoming intrusive.

Troell is best known in this country for his two-film saga, “The Emigrants” and “The New Land,” from the early seventies, featuring Max von Sydow and Liv Ullmann. Now, as he nears eighty, he’s offered another period drama that’s almost painfully real, and as insightful about the plight of women at the turn of the last century, torn between traditional expectations and new possibilities, as his earlier work was about the immigrant experience. “Everlasting Memories” is a quietly eloquent film, both in subject and cinematic expression.