Chavela Vargas said she wasn’t making a statement with her attire. “Dressed as a woman, I looked like a transvestite.” (Ysunza/Music Box Films)

At the peak of her initial popularity during the 1950s, Mexican singer Chavela Vargas wore trousers and a poncho as she huskily crooned lost-love ballads to women. Yet she didn't announce that she was a lesbian until 2000, at age 81, after a comeback bolstered by Spanish auteur — and subculture champion — Pedro Almodóvar. In between, as the capable documentary "Chavela" recounts, Vargas spent years in musical obscurity and personal anguish.

Isabel Vargas Lizano was born in Costa Rica to pious parents who were embarrassed by their boyish daughter. She ran away to Mexico City to sing on the streets, like kindred spirit Edith Piaf in Paris. Turning to the "canción ranchero" style, Vargas became known for her interpretations of José Alfredo Jiménez's yearning love songs, performed without altering the female pronouns.

She wasn't making a statement with her attire, she recalls in a frank 1991 interview that's the centerpiece of Catherine Gund and Daresha Kyi's film. It was just that, as Vargas explains, "dressed as a woman, I looked like a transvestite."

A star of cabaret stages and "macha" screen roles, Vargas was also known as an aggressive seducer. Her reputed lovers include the painter Frida Kahlo and Ava Gardner, one of the Hollywood notables who enjoyed the privacy then offered by Acapulco.

Vargas was notorious for beguiling the wives of powerful men. It's said that she was once blacklisted by a music executive whose girlfriend the singer stole from him. But the cause of her eventual downfall might be simpler: tequila.

In the late 1970s, Vargas, who had become an impoverished alcoholic, left the music business for about 15 years, living in a small, rural town. The singer credited local shamans for dispelling her addiction, but a former lover, lawyer Alicia Pérez Duarte, says it was her ultimatum that made the singer quit booze.

Vargas's androgyny and self-dramatization mesmerized Almodóvar, who met his idol when she made her first trip to Madrid in 1992 and later helped her fulfill a dream of performing in Paris. "She was like a priestess," the filmmaker swoons. "She absolved you of your sins. Then she encouraged you to commit them again."

She had just returned to performing when Vargas agreed to the 1991 interview with Gund, who had no particular plans for the footage. It was only after the singer died at 93 in 2012 that Gund recruited Kyi to make this movie, adding archival film and photos, along with interviews with such central figures as Pérez Duarte and Almodóvar.

The result is a solid if conventional bio. In the artiest touch, English lyrics tumble across the screen as Vargas sings of loss, loneliness and solitude. The feelings the vocalist expresses seem truer than the biographical details Gund and Kyi have assembled — but not fully decoded. Perhaps it's appropriate that "Chavela" leaves its reclusive subject still something of a mystery.

Unrated. At Landmark's West End Cinema. Contains partial nudity, discussion of alcoholism and an abusive relationship. In Spanish and some English with subtitles.

93 minutes.