There are film geeks and there are film geeks. The latter will be more appreciative of this insiders’ history of the National Film Registry, guaranteed to delight any librarian or archivist you know. What do To Kill a Mockingbird, Michael Jackson’s “Thriller” video, and the Zapruder footage of JFK’s assassination have in common…?All were selected by NFR committees for inclusion on the hallowed list, which basically defends then against future commercial meddling, houses the prints in a Virginia vault, and restores them. (The NFR was chartered by Congress in 1989 in response to Ted Turner’s colorization of old classics in his recently acquired MGM studio library; today, its budget is subject to cuts.) Critics, historians, and filmmakers are appointed to the committee in rotating terms, and their nominations over the past two decades are a great way build your Netflix queue. But, be warned, not only Hollywood classics like The Godfather and Citizen Kane are represented; there are also newsreels, home movies, and nitrate ephemera rotting in their film tins. These Amazing Shadows is a worthwhile but self-serving infomercial for the NFR (and its continued funding), as solemn as the Registry itself, but not without unexpected grace notes–like the animated pre-show musical ditty Let’s All Go the Lobby, which you can still find on YouTube. Because history tastes better with candy. BRIAN MILLER (Harvard Exit: 1:30 p.m. Mon., May 30.)