High Dynamic Range (HDR) has been praised by filmmakers for its shadow detail, but is that truly HDR’s crowning achievement? In this collection of thoughts from colorists, consultants, cinematographers, researchers, industry organizations, studios and manufacturers, we explore whether this obsession with “seeing into the shadows” overlooks HDR’s real potential.
The “Shadows” Camp
The visual benefit of HDR is mainly “about increased shadow detail.” Joshua Pines, Color Scientist, Picture Shop, in etcentric (Feb. 2016)
“HDR is about shadows and all the nuances we can now play with thanks to the extra bits available. I don’t understand why there is so much interest in brightness that it can be about special effects at most.” Mike Chiado, CTO, Company3, in DDay.it (Jan. 2024)
“Everyone likes to talk about the bright whites in HDR, but I think perhaps the added range in the shadows is more interesting and more important than added range in the highlights.” Erik Messerschmidt, DP, in American Cinematographer (Dec. 2019)
The “Highlights” Camp
“While there are several key quality dimensions and creative opportunities opened up by HDR, one of the key differentiators from SDR is the ability for more accurate rendering of highlights.” ITU-R BT.2390
“HDR’s consumer appeal is based upon image elements that are considerably brighter than the portrayal of diffuse white, having as much as three or five times higher luminance.” David A. LeHoty, Charles Poynton, Comparing Displays Using Luma Contours and Color Volumes, Information Display, Vol. 36, Issue 5 (Sept. 2020)
What makes a night-time image, or any picture in which dark regions predominate, an HDR image rather than merely a dark SDR image, is that there are also very bright pixels. Van Der Vleuten Renatus Josephus, Nijland Rutger, Tichelaar Johannes Yzebrand. Philips, Multi-Range HDR Video Coding (Nov.2020)
“Peak Luminance is one of the first specifications to consider when choosing a display as it’s one of the main components that describe HDR imagery.” Dolby Professional, HDR Display Considerations (Jan. 2025)
“One essential part of HDR is to render highlights, such as specular reflections, in images above the diffuse white level.” Kenichiro Masaoka, Gamut Rings Color Scope, Information Display, Vol. 40, Issue 1 (Jan. 2024)
“Formally, one can define the luminance dynamic range as the span of all luminances from a minimum black (MB) to a peak white or peak brightness (PB), ergo, in principle one might have HDR movies with very deep blacks. Pragmatically one may define, and handle, e.g. color process, the HDR images mainly on the basis of a sole value, namely being a higher peak brightness (usually this is what users are most interested in, whether it be bright explosions or merely the more realistic specular reflection spots on metals and jewels and the like, and one may pragmatically state the minimum black to be the same for the SDR image and an HDR image).” Nijland Rutger, Improved HDR Color Processing for Saturated Colors, Philips (Jan. 2021) [boldface type added]
“While HDR includes increasing the range at the dark end as well as the bright end, one of the unique attributes of HDR is more accurate rendering of highlights than traditional video. Such highlights include both specular reflections as well as emissive objects (visible light sources) and can require very high maximum luminance.” Scott Daly. Allison, R., Brunnström, K., Chandler, D., Colett, H., Corriveau, P. et al. Perspectives on the definition of visually lossless quality for mobile and large format displays. Journal of Electronic Imaging (2018) [boldface type added]
Full Range of Shadows & Highlights
“A High Dynamic Range System (HDR System) is specified and designed for capturing, processing, and reproducing a scene, conveying the full range of perceptible shadow and highlight detail, with sufficient precision and acceptable artifacts, including sufficient separation of diffuse white and specular highlights.” SMPTE
Obliterating the Shadow Myth
“The reality is PQ based HDR does nothing for black levels, and that is true of shadow detail too – no matter what those less knowledgeable or marketing material may say. A good example of inaccurate information used to promote ‘benefits’ of HDR can be seen in this presentation on YouTube, where improved shadow detail was stated as being an example of the benefits HDR brings over SDR… which is incorrect. The reality is the SDR image is probably just poorly graded, even potentially deliberately so, to promote HDR. HDR provides no such benefit over SDR shadow detail. And in reality, due to the EOTF curve in use on PQ-based HDR, the black under normal home viewing conditions will often be ‘crushed’ when compared to SDR versions of the same image. This is born [sic] out by the surround illumination level that is specified as being preferred for HDR as being 5 nits, while for SDR it was originally specified as 10% of the maximum brightness of the display. That large discrepancy, and shows that HDR black/shadows will often be washed-out/clipped when viewed in any environment where the ambient light levels cannot be controlled. In reality, a 10-bit SDR image will have potentially better black/shadow detail than a PQ based HDR image.” Steve Shaw, CEO, Light Illusion
In Debunking “HDR”, Steve Yedlin’s scalpel cut deeper than rhetoric ever could. At 1:41:00, Yedlin performs a live execution of the industry’s shadow fetish, obliterating the myth that shadow detail is HDR’s primary advantage:
“I’m going to make a change here. See that change? I can see it. I’m not saying it’s not there. It’s kind of subtle, right? It’s getting a little milky. So, based on that definition that they’ve got going there, that is a one thousandfold change in the contrast of this shot. [snickering in the audience]. Because the white is staying the same and the black is going from .0001 to .1. We see why that’s absurd.” – Steve Yedlin
“The black luminance level between about 0.003 and 0.1 cd/m2 does not significantly affect image quality. [When] the black level is 0.1 or higher, the preference of the image decreases. The best performance is achieved when the black level is 0.003, but there is no big difference from 0.1 cd/m2.” Ye Seul Baek, Youngshin Kwak, Sehyeok Park, Effects of Black Luminance Level On Image Quality, Society for Imaging Science and Technology (2019). [boldface type added] The test used a 65″ 3840×2160 OLED TV.
Researchers defined a model able to predict the maximum visible dynamic range for any given scene based on glare and local adaptation. The results showed that, while there is a non-negligible loss of visibility in brighter parts due to local adaptation, the greatest decrease in perceived dynamic range compared to the physical DR occurs in darker scene regions due to glare. For some scenes, the physical and the visible dynamic range are nearly identical, while for other scenes the visible dynamic range is half that of the physical range. Vangorp et. al. A Model of Local Adaptation (Nov. 2015) [boldface type added]
The Practical Viewing Environment Problem
“Whilst grading suites provided precisely controlled equipment and viewing environments, the same is not true for most home viewing. Low luminance images where the subject and relevant surroundings cannot be clearly distinguished cause frustration and complaints from viewers.”
“Content should be suitable for viewing in ordinary home viewing environments, where controlled, low lighting cannot be guaranteed, and display technology will vary. Particular care must be given to shadow details, with consideration to what is inconsequential image information and what needs to be preserved through re-encodes and consumer TV presentation.”
“Note that nuanced shadow detail can be lost through encoding and consumer TVs often emphasise objectionable banding artefacts in shadow detail, which can be more apparent where midtone information is scarce.” Technical Specifications for the Delivery of Content to Sky UK (Mar. 2023)
“Let’s talk about black levels. A typical HDR monitor has a black level of 0.1 nits. A high-end HDR monitor can go to 0.01 nits. So let’s say you get 0.05 nits black and 1,000 nits peak luminance: 14 stops. Mid-range HDR: 0.1 nits black, 500 nits peak, 12 stops. The natural conclusion is it’s not bad. Well, this is the ugly shadow problem. Ambient light decides how much you see into shadows. Rec. 2100 defines peak luminance 1,000 nits or greater; black level 0.005 nits or less: 17.5 stops. Most HDR is geared towards shadows. The increase from Rec. 709 highlights is only three stops. The remaining advantage, over 7.5 stops, is shadows. Rec. 2100 specifies surrounding light should be 5 nits to see shadow details. The only way is a completely dark environment. A lamp or window light delivers 50 lux, equivalent to 15 nits. A monitor 10 feet away from a white wall gets back bounced light. An HDR TV outputting 1,000 nits gives 40 lux; 500 nits gives 20 lux. Both exceed Rec. 2100’s 16 lux limit and Netflix’s 10 lux. You’ll obliterate shadow detail. Assume 50 lux: 15 nits. The difference from 0.005 nits to 15 nits is 8 stops. Whatever 7.5 advantage in shadows, you won’t see compared to a normal monitor.” Sareesh Sudhakaran, Founder, Wolfcrow Studios, “What is HDR and is HDR worth it? You’re welcome.” YouTube (2017)
The Consumer Verdict: Highlights Drive Preference
Even in a Dolby Cinema with a claimed 0.0001 theater black level, moviegoers never benefit from it, because of the auditorium’s light pollution, including exit signs and reflections off the audience from bright imagery. If we glance at Dolby’s notorious graph from their study of viewer preferences for highlights and shadows, we see that SDR’s modest .1 nits already satisfied a whopping 50% of participants, whereas somewhere in the neighborhood of 2,400 nits, or 24 times the peak luminance of traditional SDR displays, were required to satisfy 90% of all viewers (for diffuse white!), which indicates that highlights are, as Charles Poynton has pointed out, HDR’s chief appeal to consumers. 1,000 nits only satisfied a paltry 20% of those taking part in the study. In other words, HDR content does not necessarily need to be mastered to .0005 nits in order to be perceived as being of sufficiently differentiable higher quality than SDR, but luminance levels appreciably greater than diffuse white are absolutely necessary. Lastly, shows with prolonged dark scenes will cause all flagship OLED TVs in 2024 to dim down over time, ruining picture quality.
The Daejeon Chronicles 