Making lookup tables for these historic film processes involved a lot of research and color science. The other thing that was important to me was matching the grain structure of film in the digital sections. So, the look of the movie evolves through the lookup tables for the different eras, and then the whole second half was shot with motion picture negative. The visual arc starts with a colorful look for the excitement of Frank Sheeran's youth, and gradually transitions into a desaturated look, with less contrast and more grain or texture, as he gets older and it becomes a reckoning of a life past.
Do you work with the camera differently when it's digital and when it's film?
When I shoot on film, and I operate the camera, I actually see a much clearer image through the eyepiece. I also connect more to the actors, and I get a better sense of the lighting than if I'm operating a digital camera. Usually, I don't like operating digital cameras, because I'm seeing a bad little monitor that doesn't give me a good representation of what the lighting is doing, or the performance of the actors.
I remember one scene in an airplane, where Sheeran is going to Detroit to kill his friend Hoffa. I'm shooting a close-up and Robert De Niro comes in, he sits down, and he doesn't do anything, he's just sitting there. He doesn't do any expression, he doesn't do any "acting" and yet I saw all the emotion through the eyepiece. I saw his history, this whole friendship he's had with Hoffa, who's almost a mentor to him, and the knowledge that he has to kill him. I saw it all through the eyepiece of the film camera, and that's something I don't know I'd have gotten with digital, even on a monitor.