Why HDR Production Monitors Matter, Part I
“Unnecessary.” “Not possible.” “Fantasy.” Those are the words of a director of photography, slumming in L.A. since wrapping up shooting of a satirical period piece for Hulu, used to describe on-set HDR monitoring. Costly, sure – but unnecessary? Once you say that, it really doesn’t matter what you say next – because once you refuse to acknowledge the need for something, you’re part of the problem. Not to mention that it’s not the consensus of leading industry professionals.
It’s been two years since Light Iron co-founders Michael Cioni and Katie Fellion described the rationale behind LINK HDR at the ASC Clubhouse in Hollywood. “Over 150 million HDR devices are connecting and playing from OTT platforms every month,” said Fellion. “Because of that, we want to make sure we have an end-to-end HDR system, from on-set to editorial into finishing,” adding that the number of HDR-capable devices will “increase astronomically” with smartphones and other mobile devices introducing “billions of viewers to HDR.” Cioni added that “the adoption of 4K HDR is happening over 60 percent faster than that of SD to HD. By the end of 2019, over 30 percent of North America will have 4K HDR TVs in the home. And the mobile device industry is only one or two cycles away from HDR, depending on the carrier. Once it becomes a global standard, how do we respond to that and make sure images look exceptional on set?” As of this writing, more than a quarter of devices connected to streaming giant Netflix are configured for HDR and the network currently has over 1,000 hours of HDR programming available, including over 386 HDR movies, TV series and specials.
One of the things that people get confused by is that they think, ’Well, if 90 percent of the people are going to be watching the SDR, then I’ll just view SDR on set, and I can stay in my comfortable paradigm that I’ve been working in for a long time. We’ll just make the HDR coloring look similar to the SDR.’ But, that’s actually not the case. In Dolby Vision and most of the true HDR workflows, your camera negative is mapped into HDR color space first, and from there the SDR is derived. That SDR version has nothing to do with what you see on set if you’re dealing with a Rec.709 LUT. – Armando Salas, ASC, Cinematographer, Ozark
Tim Stipan of Company 3, who has worked on all 30 episodes of Ozark adds, An HDR grade is so much easier when the DP has set the light values in HDR [during the shoot]. I don’t have to work the digital negative as hard. Monitoring in HDR while shooting is a luxury, and a lot of productions aren’t doing it, but they end up spending more time in color correction trying to mitigate issues of blown-out highlights. Those color correction hours versus having a HDR monitor on set is something to be considered. Ultimately, the images will look better if the DP, DIT and gaffer can work together to create the best HDR version, then dumb down from that for the SDR version.
I was at a panel yesterday on HDR where they were saying, ‘Well you know, you don’t really need to monitor on the set, you just expose properly and everything is fine,’ and I vehemently disagree with that. I had a DP in Munich recently, we have a Dolby grading suite and he brought some footage from his latest movie and he has one scene where there was a slow dolly truck there’s a lady sitting at a desk with a laptop and a bright window in the background with the sun. So he starts out with no sun in the camera, the sun hits the camera, you get tons of flares and the laptop covers… He kind of moves around Tori, she’s sitting there, half her face is lit by the sun, there’s no way you can predict in SDR at what point in the scene you’re going to get into trouble in HDR. – Marc Shipman-Muller (Product Manager Camera Systems, ARRI)
If the director and DP of an HDR production genuinely want to shape the look of the image from the start, viewing in SDR on set is woefully insufficient. Which may account for the fact that so many HDR productions fail to thoroughly exploit the dynamic range that HDR is truly capable of – and that viewers have come to expect. Most of these shows continue to be lit in an SDR environment, they’re monitored in SDR, and the very first time anyone sees it on an HDR display is in the grading suite. This late-stage appraisal of HDR can uncover problems that were not apparent during on-set monitoring in SDR, requiring unplanned work in VFX, unexpected redelivery costs, and unintended creative compromise. DP Erik Messerschmidt sheds some light on why on-set HDR monitoring is emphatically not unnecessary:
For season two, we knew we were going to finish in Dolby Vision HDR from the beginning. With that in mind, and taking what we had learned the first season, I did extensive testing prior to our preproduction period to explore how it might affect my lighting and exposure. I worked with the DI colorist, Eric Weidt. He and I developed a color pipeline and on-set monitoring system that allowed us to monitor in HDR using an ACES workflow in Dolby PQ gamma and Rec.2020 color. For us, the setup worked great and I’m really proud of what we put together. We settled on the Canon range of HDR field monitors with the DP-2420 as our primary monitor. If one is going to finish in HDR, I believe it’s absolutely essential to monitor in HDR on the set, as HDR directly affects lighting ratios and exposure. During the DI of the first season I found we were stretching our highlights out to fill the added space in the HDR gamma space, which sometimes led to odd-looking practically lit night interiors. That is because, in most cases, I was not making full use of the sensor’s contrast, because my lighting choices were informed by an SDR monitor and waveform. Conversely, when monitoring in HDR I found I was less concerned with highlight detail, because I could see exactly where my exposures fell relative to the gamma of the final finish, and therefore was able to use more of the sensor’s dynamic range. It meant much less fill and more “exposure to the right” while still feeling confident I could work in the toe of the exposure range for most of the scene’s action. – DP Erik Messerschmidt on Mindhunter
And it doesn’t end there. While colorists do have access to the tools to see HDR, that alone is no guarantee that the master file will end up preserving all the dynamic range, tonality and color envisioned by the director and the DP. For example, the decision in post-production to constrain the levels in the HDR pass to maintain consistency with the SDR version (for reasons both technical and aesthetic) can prevent HDR from taking wing. Not infrequently, a project gets the green light for an HDR master after the fact; both the post-production house and producer preemptively rule out a version that dramatically departs from the SDR version; the result being that HDR turns out to be little more than a marketing gimmick. Another seldom discussed issue is that colorists are resorting to compromising their HDR grades in order to avoid judder artifacts. On the other hand, an SDR grade derived from a Dolby Vision master will inevitably equal or surpass a ‘hand-graded’ SDR version.
When you’re on set, you need a reference monitor that is able to show and convey, all the different tonal and color elements that you’re working with to create your look, from HDR to wider color gamut, whatever that may be, so that you feel comfortable that you’ve made the correct creative decision. An SDR proxy may constrain the enhanced aesthetic/emotional impact that is possible with the full HDR image reproduction. – Curtis Clark, ASC
One need only compare DP Manuel Billeter’s work on Jessica Jones, remastered in Dolby Vision after the fact, to Iron Fist, conceived in HDR from the outset, to see the dramatic difference an end-to-end HDR workflow makes. Billeter had to visualize scenes differently from before, and audiences can witness that in the number of sets with bright sunshine which would have been unthinkable in the past.
At a bare minimum, the editing suite should also be furnished with a consumer HDR TV, as cuts between bright and dark scenes have a different impact on the viewer. Instead, what ends up happening is that 99% of HDR films on Netflix and elsewhere, while technically HDR, are in reality little more than SDR with a few specular highlights thrown in here and there. In 2016, SpectraCal published a paper in which they focus primarily on the technical hurdles:
“Most digital cinema cameras today can capture at least 14 stops of exposure range, but this wide dynamic range is not currently preserved, even for cinema presentation. HDR grading for the home can be delivered with 8-10 stops of exposure range… HDR TV is also not primarily about overcoming limitations on the playback end… Current displays can produce greater dynamic range than the current specifications for the content distribution chain can handle… The main challenges that need to be addressed to enable HDR TV are primarily the specifications and systems for the middle processes of mastering, encoding and delivering TV images to consumer display devices.”
We’d argue that today, combatting complacency is the greatest challenge. The good news is that, as the audience for HDR grows; as the price of HDR production monitors falls; as innovative solutions like LINK HDR and dailies platforms Frame.io, FotoKem’s Next Lab, FilmLight’s Prelight On-Set, Colorfront’s On-Set Express Dailies, MTI Film Cortex Dailies and Moxion continue to evolve; and as DPs do give a damn about stuff like lighting ratios, on-set HDR monitoring will eventually become the norm.
Why HDR Production Monitors Matter, Part I