Fine-Tuning the Digital Image for Benjamin Button
How Lowry Digital Integrated its Process With DI and VFX
ALAN SILVERS: More and more all the time. We have unique tools that let us work with imagery independent of the grain and noise. We can find detail in your pictures that you don’t know how to get to, and bring it out. And we have proprietary methods of dealing with artifacts that are unique to this facility. As we move more toward an all-digital pipeline, these tools have application at the front end of current-release production and post. People are shooting HD and going to large format. They’re shooting Viper and going to 35mm. They’re integrating HD or sometimes lower-resolution visual FX. In these and many other instances, people need to deal with resolution and detail issues.
AS: It works in concert with the DI. People are finding that the world of displays is changing. We used to have SD at home and watch 35mm at the theater. Now we have digital cinema and HD monitors in people’s homes. The display characteristics of digital cinema and Bu-ray are radically different than what we’ve seen before. Film is very forgiving, and a digital-cinema print can show artifacts you wouldn’t see on film. Standard-definition television hid a multitude of sins. So we can work with the editorial, conform and color-correction aspects of DI, but add an image-processing pass that will ensure high-quality pictures regardless of your need to up-res, or capture challenges you’ve found. And we have a good handle on what happens to your movie when it goes through compression engines for Blu-ray, digital cinema, or the Web. We can reduce noise, enhance fine detail, remove artifacts, and stabilize imagery – anything that’s going to remove redundancy from frame to frame. You can have shots of a still life, but if the grain pattern fluctuates, that will affect how the compression engine handles it.
F&V: You don’t want to go so far that you take the life out of the picture.
AS: We don’t make creative decisions. We only make them in the context of what the filmmaker is after. We encourage as much interaction as we can so that we apply the tools exactly in the way the content owner wants to protect the integrity of their photography. Pat [Cooper] had regular dialogue with post supervisor Peter Mavromates and other folks involved with the DI. Button had some interesting challenges because it takes place over eight decades, and a big part of what we were asked to do was to unify the look of the film within each decade.
F&V: You had worked with David Fincher previously on Zodiac. How did you get involved with that film?
AS: Initially we were contacted because David had a couple of issues on set.
Pat Cooper: We were able to address a number of issues that were present in their imagery. There were chromatic aberrations from some of their lenses, so many shots had what looked like an out-of-register image where you would see blue fringing on one area of the picture and red fringing on another. We were able to correct those. On some occasions, maybe the power supply was acting up and they’d end up with flicker in the picture, which we would remove. We used filters to knock down overshoots and repeating vertical patterns. Also, if you start to really push the camera to itsl imit in a very, very low-light condition, there are patterns that are present in the CCDs in the camera, and you can end up with a screen-door-looking pattern over the image. We have a filter we’ve deveoped to take out that screen-door CCD pattern as well.
And they had varying amounts of noise from shot to shot. It looked very practically lit – they would actually light scenes with only a couple of 60-watt light bulbs. The ability to shoot in low-light situations is one of the main advantages of digital cameras. But they ended up with a lot of differences from shot to shot, because you have to turn the gain knob up and down to cope with a low-light situation, as opposed to taking a daytime shot on the street in San Francisco, for example.
So we unified the look of the picture. We took down the noise and enhanced the pictures to achieve an even amount of sharpness shot to shot. We put an even amount of grain on top so it had a film-grain distribution as opposed to a video-noise distribution. On some occasions, maybe the power supply was funky and they’d end up with flicker in the picture. If you start to really push the camera to its limit in a very, very low-light condition there are patterns that are inherent to the CCDs, and you end up with a screen-door pattern over the image. We have a filter we developed to take out that screen-door CCD pattern.
We did a number of iterations, with tests both to film and digital cinema screenings with David and Peter, to set the look. How much sharpness and how much grain did they want? Once the target had been set, we went through and used those as benchmarks for the aesthetic look. We then noise-reduced the movie, took out all the flicker and artifacts, and then put in an appropriate amount of noise for seamless transitions from shot to shot. This way, you wouldn’t be shocked by a sudden change in quality when it cuts from a slow-motion shot at nighttime to a regular-speed shot in a more well-lit area.
F&V: Were you involved during production on Zodiac, or just in post?
PC: More in post-production. Originally, we were only to be involved only with shots they saw as problematic. Once we did a demo for David and Peter, they decided to use us for the whole movie. When it came time to do Benjamin Button, there was a re-affirmation test with David and Peter. David wanted to be sure that he was making the right decision by coming back to us. We did a round of tests for a lot of their early cinematography across a wide variety of shots. And David was convinced.
F&V: On Benjamin Button, how did you work in conjunction with the DI process?
PC: The DI was done at MPI. My understanding is they would do all the editing and conform over there, and then they would do a near-final color-correction on, effectively, the raw Viper imagery. Once they had the conform set and the near-final color correction applied, they would send us sections of the film. We got it in bits and pieces – 5000 frames this week, 20,000 frames next week – after primary photography had been completed. We would take those conformed near-final-color sections, apply the Lowry process, and then sent them back to MPI, where Jan Yarbrough, the colorist, would dial in the color exactly. You might need to do a little bit of touch-up color-correction if the imagery has a very intense sort of grain in one particular channel. For example, if you have a high level of noise in the blue channel, your eye averages that out to make the image look more blue, and you color-correct that. In that particular example, when we even out the amount of noise between the red, green, and blue channels, it now looks a bit more yellow in cast, and you need to adjust the color-correction slightly.
F&V: What about working with the VFX vendors?
PC: We would normally get un-corrected, raw Viper images, typically for backplates but sometimes for shots that had blue-screens in the background. We would noise-reduce those shots and sharpen them up without adding any grain on top. That way the compositors had a very clean shot to work from. They could pull masks easily for green-screen or blue-screen work with no noise on top to complicate that part of the process. They also now had a sharpness target to match for their composited-in elements that would help make the final composite as seamless as possible. We got back what were effectively noise-free finished composites cut into the main body of the movie. At that point we knew we had done the noise reduction and enhancement, so all we had to do was put an even amount of grain on top to match the surrounding shots.
F&V: What kind of shot-by-shot guidance did you get from the filmmakers?
PC: They wanted us to be very careful that we didn’t oversharpen shots with a lot of makeup or CG head replacement. We are conscious of that anyway, but they wanted us to be extra careful. “Look, please do not overcook these shots, do not oversharpen them.” They spent a lot of time and money making those look just right. We spent a lot of time with a shot-by-shot enhancement to make sure the imagery was as even as possible, but also to make sure that we didn’t go overboard as far as oversharpening the shots that contained a lot of special effects or makeup.
F&V: Did you touch every shot in the film?
PC: No, there were plenty of shots we did not touch. For the 2005-era hospital sections of the movie, we only processed the very beginning sequence. We did not process most of the hospital scenes. There was also one sequence – a love scene with Brad and Cate in a four-poster bed – where they liked how it looked right out of the camera so we did not process that scene.
AS: David shot some film, too, which we didn’t do.
PC: The Mr. Daws shots with the lightning strikes, where it looks like old-timey 1914 cinematography? We didn’t do any of those. There was actually a lot of slow-motion and other cinematography that demanded film camera mounts – one was mounted to a machine gun, where you would probably destroy a digital camera if you subjected it to those shocks and vibrations. They shot film on a small amount of the movie, and we were able to mix and match that with video with Viper-captured matierial that had radically different resolution and noise and grain and sharpness characteristics and have t appear as seamless as possible when cut into the movie.
F&V: The end result was very nice ‘ it had its own look, and it wasn’t harsh. It didn’t look like video. And it didn’t have much noise in the shadows, which is something I often expect to see in HD films.
PC: That’s part of what our process does. We take all the noise out, then put back in as much as they want. They didn’t want a whole lot of grain back on the picture. They wanted a relatively clean look, so that’s what they did. I can’t say enough good things about the amazing underlying imagery [shot by D.P. Claudio Miranda] that we started with – it’s easy to make material of that quality look good.
AS: It’s interesting to note that it’s one of the first digitally captured movies nominated for [an Oscar for] Best Picture and Best Cinematography, along with Slumdog Millionaire. And that’s pretty rare company – for people to look at it and not feel like digital capture got in the way.