Aplomb is basic to ballet, so obviously it matters a lot to ballet movies. Nancy Buirski’s documentary accordingly suggests that the true story of Tanaquil Le Clercq — the story of a great ballerina paralyzed by polio — is only as tragic as the ballerina herself decided it would be. Using speaks-for-itself footage of Le Clercq in her signature roles, and readings of her reflective and exceedingly romantic correspondence, Buirski easily affirms that the dancer’s angular sensuality was but one aspect of her enduring creative power. Another was an impishly tenacious spirit, and if some of Buirski’s character witnesses seem perpetually at risk of sinking into self-seriousness, balance is repeatedly restored by the practically supernatural buoyancy of Le Clercq. Of course it helped that two of the most important men in her life were also two of the century’s most important choreographers, George Balanchine and Jerome Robbins. “Her talent could take in almost anything,” Robbins once said, very clearly including his candid choreography of that modern-ballet staple Afternoon of A Faun, from which Buirski’s film takes its title and in which Le Clercq’s performance was riveting. A tip of the hat to Vaslav Nijinsky’s 1912 version for the Ballets Russes — and, for that matter, to composer Claude Debussy and poet Stéphane Mallarmé — might have been nice here, but it’s hard to fault Buirski’s admiration for the way Le Clercq made everything seem completely her own.