David Fincher’s keenly anticipated Netflix original “Mank” is a valentine to old Hollywood glamor in the shape of a character study of the larger-than-life screenwriter of Orson Welles’ “Citizen Kane,” Herman J. Mankiewicz, played with gusto by Gary Oldman. Speaking in an online seminar at the EnergaCamerimage Film Festival, cinematographer Erik Messerschmidt (“Mindhunter,” “Gone Girl”) […]