“Green’s revision of that record is long overdue and just in time, given the present-day reckoning with Hollywood’s stubborn traditions of behind-the-scenes (and onscreen) sexism. Most intriguing are the clips the documentary gathers from Guy Blaché’s films. Many of them look less like old curiosities than lost classics, and their range — from the surreal slapstick of “The Drunken Mattress,” to the domestic melodrama of “Falling Leaves,” to the social satire of “Consequences of Feminism” — is astonishing. (Several have been issued by Kino Lorber in the indispensable “Pioneers: First Women Filmmakers”collection). By the end of “Be Natural,” you won’t only have a clear idea of who this remarkable woman was; you may well have acquired a new taste in old movies.”