The effect is really head-turning when you see the film on film. If the print's undergone some wear and tear (like the one screening at the Siskel Film Center this week), some of the images are just mind-boggling. Which filmic qualities were created synthetically and which ones are the natural result of aging celluloid? Fincher and his effects team inspire in the viewer, even if only subconsciously, a feeling of implacable suspicion. This seems appropriate for such a paranoid film—which is, indeed, so paranoid that it second-guesses all its own leads.
Since Zodiac, multiple digitally shot movies have attempted its faux-celluloid look. None have demonstrated Fincher's meticulousness or sense of thematic purpose. James Wan's The Conjuring is the most inept of the rip-offs I've seen, as it demonstrates no feel whatsoever for 70s cinematography—its aesthetic, to the extent that it has one, is a pastiche of a pastiche. Perhaps The Conjuring would look somewhat better if it were transferred to film; the projection format might add a few traces of authenticity (even if it wouldn't trigger the sort of head-scratching that Zodiac inspires.) Yet few audiences are likely to experience the movie this way, as new American releases are increasingly exhibited in digital formats.
Within a generation, the very idea of digitally shot movies transferred onto film will feel like the byproduct of a transitional era. I predict that Zodiac, like Godard's In Praise of Love (2001), will be seen as one of the works that took full advantage of the transition to create textures unlike anything movies offered before or after.