HDR (High Dynamic Range): From Too Bright to Just Right
Really Seeing with HDR
It seems like every year there’s a new buzz word at NAB. One year everyone had a new camera crane… then everyone had a 3D rig… then it was 4K… then drones. This year it was HDR… and I’m sure by next year it will be ubiquitous.
HDR (High Dynamic Range) has been around for image capture for a long time. The dynamic range of cameras has been increasing every year, always trying to emulate the benchmark of film… and now surpassing it.
But we’ve never had viewing devices to see all this new data. Up until now with Rec 709 TV or 14 foot-lambert cinema projection, we’ve had to “unnaturally” compress the new found range into the old contrast (gamma) curve or throw it away. And when I say throw it away, I mean just using the range for exposure latitude.
But suddenly with advent of laser projection and HDR TV we are suddenly able to “display” images at ranges much closer to how the eye perceives them in the real world.
The first HDR images I saw at NAB a few years ago were from the Dolby Pulsar 4000 nit monitor.
That’s pretty damn bright, and at the time I didn’t like it. I asked myself: “Are those highlight pings coming off the cars in the background, searing my eyeballs, really helping me appreciate the story I’m watching?”
So to begin with I was not a big fan. The first time I saw HDR projection and liked it, was about a year ago with a prototype laser projector that Dolby had installed at the Vine Theatre on Hollywood Blvd. They demoed some footage from Star Trek and I was quite impressed. Dolby is partnering with AMC to build laser theaters with Dolby Atmos sound.
An Industry Screening Changes Bruce’s View
But Imax might be a little ahead of the curve although not true HDR… I went to an industry screening debuting the new Laser projection at Mann’s Chinese Theatre. Their demo film was amazing in 3D also with Dolby Atmos sound that seemed to come from everywhere.
Following the demo film was an advance screening of “Furious 7” and I swear half the industry audience didn’t take off their 3D glasses, even thought the film was in 2D. I did… and the new Imax Laser Projection was fabulous.
A Colorist’s Philosophy
My philosophy as a colorist has always been to compress my color pallet into a narrow range like the old masters did on canvas. A fine Pissarro painting had maybe a two stop range from black to white. These painters didn’t have HDR paint and it always astounded me that they could make a six stop range replicate scenes that I perceived as bright sunlight. And I’ve tried to do the same thing as a colorist.
I’ve finally been involved in grading footage specifically for HDR display and today I was able to see this footage on several different manufacturers equipment set up at the ASC Clubhouse.
Behind the Scenes at the ASC Clubhouse
The ASC Technology Committee, of which I’m a member, led by Curtis Clark along with Gary Demos, Bill Mandel, Harvey Landy, Joe Kane, and Holly Lowzik managed to get six major manufacturers into the same room, all displaying their latest prototype HDR monitors and TV sets. This is unheard of, and very brave of the manufactures.
The content that was being screened was the ASC/PGA Image Control Assessment Series, or ICAS material which I helped write, direct, and subsequently grade. By grading specifically for HDR Display, we were able to use the range when we wanted to and not when it was annoying (hot pings of sunlight on cars).
Shooting and Grading HDR
The PQ curve developed by Dolby is the “gamma curve” for HDR. It was fascinating seeing the scope while grading…where the normal 0-100 IRE of Rec 709 is just the bottom third of the scope and the HDR scope goes up to 10,000 IRE. This graph gives you a great view of the contrast ranges of different displays.
One of the scenes written and directed by me and shot by Robert Primes, ASC, was an interior restaurant looking out into a bright street. The first thing that the HDR did was to bring a fantastic depth to the scene, almost like 3D but without the inconvenience of the glasses.
The second scene written and directed by Fred Goodich, ASC and shot by Nancy Schreiber, ASC and Steve Mason, ASC was a dark night exterior with massively bright light-sources: headlamps, fire, neon and fireworks. I have to say seeing this scene in HDR was the first time it came to life for me and even though the light sources were extremely bright.
The problem of showing images of these scenes is that the device that “you” will be looking at them on is not HDR. So I apologies for the lack of relevant imagery in this blog.
HDR Innovation Driven By Commerce
I have to say that this surge in HDR is driven by the manufacturers. They have to find a way to sell new TVs. The sets can’t get much bigger, 3D TVs have peeked without much interest, so HDR is the new technology in town.
And we got to see sets from:
SONY showed their gorgeous, very bright (they don’t want to say how bright) X940C 75 inch LCD which will retail for $7,999. The HDR will come as a Firmware update later this year. And their Pro HDR color suite monitor BVM-X300 which delivers almost 1000nits.
CANON showed their Pro color suite or on set 4K LCD DPV2410 monitor. It boasts 400nit. Rec 2020 colorspace. And it willdebayer raw camera data in real time.
PANASONIC Showed their UHDHDR TV.
LG showed their HD Oled TV
SAMSUNG showed their JS9500 4K (actually UHD which is four times HD). They were the only manufacturer that didn’t turn off their Motion Interpolation, which gave them a leg up on everyone else. Everyone had been asked to turn theirs off. But Samsung weren’t available to disable theirs.
The problem here is that the ICAS material we shot at 24 FPS with a 180 degree shutter. One of the most problematic artifacts in HDR is that the highlight strobe, sometime quite violently with fast action. This is because a high contrast object always strobes more than a low-contrast one. And of course HDR is all about high contrast.
When Samsung turned on their Motion Interpolation, the strobing went away. Problem solved? Well not for me… I hate it. I don’t like my 24 frame movies to look like broadcast 60i video.
Well, that’s it for now if you have any questions you’d like to ask about HDR or anything else… drop me a line…firstname.lastname@example.org.
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