In creating a documentary portrait of a parent, as actor Charlotte Gainsbourg does in her directorial debut, one could overly flatter the subject or iron out the tough creases. Gainsbourg avoids these traps in her wise and wondrous film about her legendary mother, the singer and actress Jane Birkin. Consisting of several intimate conversations between parent and child, as well as footage of Birkin performing onstage, the result is a spare, loving window into the emotional lives of two women as they talk about subject matter that ranges from the delightful to the difficult: aging, dying, insomnia, celebrity, and their differing memories of their shared past, which includes Charlotte’s father and Jane’s husband, Serge Gainsbourg. Jane by Charlotte is an unexpected, imaginatively visualized work that affords intimate access to someone whom many of us only think we know.