Future of Cinema Panel Explores HDR in Theory and Practice for Theaters

A scene from 'The Jungle Book.'

One of the most exciting development in theatrical movie exhibition in many years — HDR (High Dynamic Range) projection – has gone from concept to reality this past year with releases in select theaters of Dolby Vision versions of major features, including Brad Bird’s Tomorrowland, Pixar’s Inside Out and the blockbusters Star Wars: The Force Awakens and Walt Disney Studios’ The Jungle Book. Filmmakers are only beginning to get a handle on the technical possibilities and requirements involved in mastering for HDR projection and developments about how to creatively use the extra dynamic range are in their infancy.

So it’s not surprising that the panel discussion on the subject during the Future of Cinema track at the NAB show Saturday was filled to capacity. Attendees were privy to a fascinating, in-depth exchange of ideas with key early adopters. Pat Griffis, VP of Technology for Dolby Laboratories, moderated the event with panelists Rick Sayre from Pixar Animation Studios, Jeroen Schulte, Image Pipeline Lead at ILM, Thad Bier Director of Image Platform Workflow at Dolby, Ben Rosenblatt, producer at J.J. Abrams’s company Bad Robot, Stephen Nakamura, Digital Intermediate Colorist, Deluxe’s Company 3, and Rob Legato, ASC, VFX Supervisor. Unlike some panel discussions where experts explain industry best practices, this one allowed attendees in on some preliminary discussions about what those practices might be… sometimes without consensus.

Dolby has been leading the way in this arena with its Dolby Vision-approved theaters, housed with laser-based projectors capable of putting images on screen with maximum screen brightness of 108 nits, more than twice the brightness of the industry standard for many decades of 48 (that’s 14 and 31.5 footlamberts for cinema technicians who didn’t get the message that it’s all about nits now). Making the images work at both 48 and 108 nits is more than just applying a LUT or transfer function; it’s about mastering versions specifically for this new space and establishing a workflow from set through VFX to final color that allows creatives the ability to shape the material specifically for this dynamic range.

A movie mastered for Dolby Vision specs can display bright whites that are roughly twice as bright as the brightest white possible with traditional D-cinema projection. It can display blacks hundreds of times darker. In prepping The Jungle Book, Legato says he and others on the project compared material projected at HFR and in HDR and everyone involved responded much more to the HDR. “The blacks were incredible,” he enthused. “The screen just disappears into this big portal.”

For the Dolby Vision version of Tomorrowland, director Brad Bird asked colorist Nakamura to boost the bright areas for certain scenes but he wasn’t interested in pushing the shadow areas way down into that space made possible by Dolby Vision: “It wasn’t that kind of movie,” Nakamura explained.

Dolby Vision can hold detail in bright areas of the frame that would clip in the 48 nits space and it can retain nuance deep into the shadows that would be unviewable within D-cinema’s constraints, but that doesn’t mean the filmmaker wants those effects. The aesthetic question then is, What do cinematographers and directors want to do with this extended range? And given that there are still very few places to see Dolby Vision projected, how much do filmmakers want to think about the 108-nits version of their films anyway?

Inside Out, Sayer added, built the increased contrast and color gamut into the film’s storytelling – there are some environments the character inhabits that simply can’t be displayed at 48 nits. Viewers lucky enough to see Inside Out at a Dolby Vision theater experienced those nuances in ways that people didn’t who saw it in standard D-cinema. Nakamura’s experiences to date have always been with filmmakers who want to get it perfected to their satisfaction “for the 99.9% of the people who will see it in regular D-cinema. Then we go in and do a Dolby Vision pass where we push things where it makes sense to push them to take advantage of the increased dynamic range.”

For Griffis, not surprisingly an advocate for making the very most possible of Dolby Vision, the best workflow would be to master for 108 nits and then derive the 48 nit version from that. Rosenblatt echoed that idea, comparing the audio workflow that’s evolved with Dolby Atmos. “At first,” he said, movies “mixed for 5.1 and 7.1 first and then went back and did a Dolby Atmos pass. But now it’s going the other way and we’re mixing for Dolby Atmos and then mixing down to the other formats.

Nakamura agreed that this could be the future, but hastened to add, “When you’re coloring a movie and a director is signing off, they’re looking at the version that’s about to open in 3000 theaters.”

From a technical POV, the panel agreed that the extra mastering dynamic range was of little use if the image information wasn’t there in the first place. The use of cheaper, prosumer cameras that might work for a standard cinema presentation could fall apart in HDR projection. This is true in VFX as well. Artists need to build dynamic range into their effects and work in files with a significant bit depth. “HDR is the ultimate bad matte painting detector,” Shulte emphasized.

Sayer agreed but pointed out that on high-end projects, VFX can and should have a lot of dynamic range built in. An advantage to creating digital images from scratch is that it’s possible to build a significant amount of dynamic range into the images. Effects teams, he said, “have designed their work with latitude already in there so that colorists and directors [push the look] in post, the images don’t fall apart. We’ve really been working in ‘HDR’ forever.”

The discussion covered many such subjects and even veered off its cinema-centric path briefly to touch on these same issues as they relate to the even more extreme potential of dynamic range for home displays, today and into the future as brightness levels in consumer TVs get to promised levels of 1000, 4,000, even 10,000 nits.

The potential for wild dynamic range approaching what we actually see in real life is tantalizing. But to what extent to filmmakers want to use this new space just because they can? As Nakamura, who’s re-mastered several feature titles for such displays, said, “If you have an explosion with a big flash, it’s easy to look at [in HD]. But at 4,000 nits, you’re going to blink. If you have a lot of guns firing and explosions, you could give people eye strain. So then the question is: Is that what you want?”

“Just because you can make images brighter, doesn’t mean you should,” Beier elaborated. He was as excited as any on the panel about the potential of HDR but he was concerned that it might, especially for the home market, wind up being overused and applied inappropriately simply because it becomes technically possible to do so. “I’m worried,” he reflected, “that the ‘brightness wars’ could become the new ‘loudness wars.'”