You don’t ask Robert Zemeckis about themes and ideas. What the filmmaker — of “Back to the Future,” “Who Framed Roger Rabbit,” “Forrest Gump” and now “The Walk” — most likes to talk about is the technical side. (J. Hoberman has said the filmmaker was even oblivious to the Oedipal subtext — really, the text — in “Back to the Future.”) He was an early embracer of digital effects and hot new technologies, and even dramas like “Flight” tend to feature extensive use of subtle CGI. Still, he maintains that he doesn’t do films to do tech; it’s the stories that grab him, with digital effects employed as a tool to flesh them out. With “The Walk,” he tells a story already told in the acclaimed doc “Man on Wire”: how French acrobat Philippe Petit (played by Joseph Gordon-Levitt) covertly strung a tight-rope between the Twin Towers in 1974 and strolled across them. But he marshals the forces of first-rate tech to put us up there with him as he struts 110 stories above the ground.
Like “Flight,” this is a live-action film reliant on sometimes subtle, sometimes not-so-subtle CGI. Could you even make “The Walk” without relying on CGI?
I don’t even know how you’d do it at all. I guess you could use miniatures. Back in the old days you’d use miniatures and process screens. It certainly would have been very limiting.
Some of the CGI in this film is about recreating things that no longer exist. You create the World Trade Center both from the outside and the inside. In the past they would just build a set. This seems…well, not cheaper…
Just because it’s digital doesn’t mean it costs nothing. You have to understand that. People can say things like, “Oh, a microphone dropped into the shot, screw it, move on, we’ll paint it out later.” Well, that costs money. Or, “Oh, gee, I made a mistake on the color of the actor’s tie. I’m going to change it from red to green.” To do that in every shot costs money. Filmmakers have to be careful that they don’t get sloppy, figuring they can change everything — which they can. But it costs money. To answer your question, basically you build what you need. So you build what the actors are going to touch, and you do a set extension. Sometimes it’s cheaper to build more stuff, sometimes it’s cheaper to build stuff virtually. It’s always a trade-off. Obviously it’s more difficult and more expensive to create photo-realistic reality. Doing s— in outer space, nobody knows what it looks like. Aliens, anybody can do aliens, because nobody knows what they look like. It’s hard to do humans.
The big walk at the end is obviously very effects-heavy, but even in the dramatic scenes, such as in Paris or on the streets of 1970s New York, there’s a lot of digital manipulation.
We shot Paris in Montreal, so in some shots all we used were the cobblestones on the street. Everything else was painted in. Digital cinema is magnificent. You can do so many great things. It’s a great tool. One of the things I love is I can shoot at a high-frame rate, and then I can adjust the speed of the camera movement. Or if an actor moves his head to react a little bit too quick, I can subtly slow it down and give it a more dramatic move that the audience can’t perceive. Sometimes an actor will have a little twitch or an eye blink at the most inopportune moment in his performance. You can change the actor’s makeup. If he has circles under his eyes you can just paint them out.
How is that for the actors, knowing their work can be manipulated?
Most actors probably aren’t aware of all the sophistication of the tools we have. But some do. I think acting is going to evolve, as with all technology. Actors in the early days of cinema had to project their voices because the microphones weren’t that sensitive. Now actors can whisper or mumble their performances so we can pick up what they’re saying. Actors will evolve knowing that digital tools can help them enhance their performances as time goes on.