PARK CITY, Utah — “The real me is not photographable.”

That’s the claim made by Benedetta Barzini in “The Disappearance of My Mother,” one of several memorable documentaries in this year’s Sundance Film Festival. A former Italian supermodel, Barzini (born in 1943) inhabits various roles in the movie, which was directed and primarily shot by her son Beniamino Barrese. Now in her 70s — and after years of being a photographically fetishized subject — Barzini has decided that she would like to disappear. “The work we’re doing,” she says to her son, “is a work of separation.”

Deeply personal and shot through with fascinating contradictions, “The Disappearance of My Mother” is a portrait of a woman in rebellion. Born into privilege — her father was a well-regarded writer and her mother an heiress — Barzini survived anorexia and indifferent parenting, and began modeling in New York in the early 1960s after catching the eye of Diana Vreeland, who was then at Vogue. Barzini worked alongside Richard Avedon and Irving Penn, but soon expanded her horizons: She studied with Lee Strasberg, befriended Salvador Dalí and hung out at Andy Warhol’s Factory, posing with Marcel Duchamp for one of Warhol’s short “Screen Test” films.

In “The Disappearance of My Mother,” Barrese selectively grazes over Barzini’s past and incorporates archival still and moving images into the mix, including some fabulous footage of her on the job. (Her geometric poses fluidly enhance the lines of the clothing.) Most of the images, though, were taken by Barrese, an obsessive chronicler of his mother. He began shooting her when he was young, turning his photographic gaze on a woman who, as she grew older, became more and more tired of being in front of the camera, to the point of hostility. She continues to model, strolling one catwalk with hauteur that edges into contempt, but it’s complicated.

[Read more from Sundance: The festival’s good (and even great) movies]

Those complications surface in the documentary piecemeal. Barzini is Barrese’s subject (and apparent muse), but she’s also his mother, which creates some productive friction. A feminist and Marxist who now also teaches, Barzini is a severe, unsparing critic of the commodification and exploitation of the female body by men, which greatly complicates her son’s insistent, at times intrusive gaze. It also deepens the movie, making the personal ferociously political. He’s forever shooting her and she routinely swats him away, asking and sometimes yelling at him to stop. Yet she also poses for him, and as her face brightens, it seems she’s not ready to vanish just yet.