When Benjamin appears in his 80s, 70s and mid-60s in The Curious Case of Benjamin Button, he is completely CG from the neck up. All Benjamin Button images courtesy of Digital Domain. © 2008 Paramount Pictures and Warner Bros. Ent.

How curious that The Curious Case of Benjamin Button, The Dark Knight and Iron Man take CG to new levels of realism to aid their actors' performances. Eric Barba of Digital Domain, Paul Franklin of Double Negative and Ben Snow of Industrial Light & Magic discuss this and much more.

Bill Desowitz: Eric, you're the frontrunner with Benjamin Button and its innovative CG head replacement work. Was there a moment when you breathed a sigh of relief that it worked?

Eric Barba: I have to say it was probably during the putting together of that shot where Benjamin is leaving the young lady of the evening. He was backing away from her and saying, "Will you be here tomorrow?" This was really a great moment. That shot came together in such a magical way and everything just worked right out of the box. There was some work obviously with the performance, but it worked with the body, and the animators finessed a little bit the nuance of what Brad [Pitt] did. That was probably when I felt the most comfortable. But when you're staring down the barrel of 325 shots, it's a bit daunting, but you can check box at least one. And David [Fincher] was very good about starting with the easy ones and I always like to start with the hardest ones because they're going to need the most care and you want to look at them the longest.

He wanted to start with some over-the-shoulders and a few of the simplest wide ones that helped prepare the team for what was coming, including the shot in the trailer when he says, "I'm 7 but I look a lot older." That one took a long time because the body actor happened to be doing sporadic movements almost as if he was so old he was shaking, and initially David thought it was an endearing quality, but when we put Brad's performance on that body, it was an example of Brad's performance not in synch with the body language of the body actor. And we kept it open so long as we tried untold revisions to match that. In some ways because you can change things, you try to see if it'll help.

Eric Barba, visual effects supervisor, Digital Domain.

BD: What was the experience like for Brad? Was it ever frustrating not being in total control of his performance?

EB: When we were shooting his performance, he didn't seem frustrated. He was genuinely happy and very...

BD: Curious?

EB: I think he was asked those questions, but he'd look at the takes and because David had already [selected] the cuts that we wanted and the takes that he liked for Brad to perform and he'd then direct him, it seemed to go incredibly smoothly and well.

BD: And what was it like working with Fincher, and waiting for technology to catch up with need?

EB: Because I started with him in commercials [in '92] and commercials are their own beast, especially with David's body of work, he pretty much gets the pick of the litter. Just working with him, I knew this was a great opportunity and that the bar was set incredibly high. At the same time, I've learned so much from him. He's really good at knowing what he wants and communicating it. After a while, I can work in shorthand with him. But on this film, we really started talking about it in early 2004, prior to doing the original test. It was amazingly daunting, especially where technology was back then. At the same time, this is what gets me up in the morning because this is the kind of work that, hopefully, will take us to that next level. So I was constantly thinking about the little pieces -- the hair, the eyelashes and glasses, the little subtleties around the mouth, the teeth and the tongue. Certainly the eyes are huge in conveying that emotion, especially since Brad's performance can be so subtle and sometimes all he does with the eyes is everything.