A Com­plete Unknown, the new movie about Bob Dylan’s rise in the folk-music scene of the ear­ly nine­teen-six­ties and sub­se­quent elec­tri­fied break with it, has been praised for not tak­ing exces­sive lib­er­ties, at least by the stan­dards of pop­u­lar music biopics. Its con­ver­sion of a real chap­ter of cul­tur­al his­to­ry has entailed var­i­ous con­fla­tions, com­pres­sions, and rearrange­ments, but you’d expect that from a Hol­ly­wood direc­tor like James Man­gold. What many view­ers’ judg­ment will come down to is less his­tor­i­cal verac­i­ty than whether they believe Tim­o­th­ée Cha­la­met as the young Bob Dylan — or rather, as the young Bob Dylan they’ve always imag­ined. Still, much depends on the rest of the cast, who por­tray a host of major folk- and folk-adja­cent fig­ures includ­ing Pete Seeger, Woody Guthrie, John­ny Cash, Alan Lomax, and the late Peter Yarrow. No per­for­mance apart from Cha­la­met’s has received as much atten­tion as Mon­i­ca Bar­baro’s Joan Baez. In those char­ac­ters’ key scene togeth­er they take the stage at the 1964 New­port Folk Fes­ti­val and sing “It Ain’t Me Babe,” a Dylan song …