Timothy Lottes Anti-HDR Rant

On December 19, Timothy Lottes responded to a Wccftech article [1] profiling graphics programmer Filippo Tarpini with a torrent of shocking distortions of fact about HDR. We break it down.

CLAIM: “The room environment is the primary thing that determines what the screen looks like.”

FACT CHECK: Largely true. You need both a capable HDR display and a suitable environment [2].

CLAIM: “Tone mapping is a marketing scam.”

FACT CHECK: Categorically false. Tone mapping is essential to adapt the luminance and color of the content to the limited capabilities of consumer displays:

“Each PQ grayscale level corresponds to a specific display light level, from 0 to 10,000
nits. The internal processing of each consumer display adjusts the highest PQ levels to fit
within the display’s brightness capability. This adjustment is called ‘tone mapping’ [3].”

CLAIM: A CRT TV measured “over 14 stops of contrast at low APL. In a dark room, contrast is effectively like an HDR display.”

FACT CHECK: Unverifiable anecdote, zero documentation. By definition, “High dynamic range (HDR)… is commonly defined by contrast and peak luminance” [4]. A CRT’s ~300-nit peak fails this. Furthermore, expert analysis confirms CRTs couldn’t achieve stable high contrast in practice due to unstable black levels and screen reflectivity [5].

CLAIM: “PQ is a horrible standard: it requires expensive shader code, the 10-bit requirement reduces FPS by 20%, it wastes digital code values on unused highlight luminance (10K nits) and shifts banding to the mid-range.”

FACT CHECK:

• The performance cost of pow (log/exp) operations in the shader is minimal on modern GPUs [6]. Lottes admits to concocting an extreme workload expressly designed to exaggerate costs: “And some of us (like myself) are targeting really low end GPUs at extremely high frame rates. I don’t want the PQ tax [7].” 
• The 10-bit requirement has a negligible impact on performance. 
• Only ~7% of PQ’s code space is allocated to the 5,000-10,000 nit range [8]. 
• The PQ curve is perceptually uniform, prioritizing more codes for the lower luminances where the eye is more sensitive:

“Unlike the encoding used in SDR, PQ concentrates the grayscale levels where your vision is most sensitive. With PQ, High Dynamic Range provides not only more digital bits, but also the most efficient use of each bit [9].”

CLAIM: “Rec.2020 wastes code values when displays are < P3.”

FACT CHECK: HDR requires 10/12 bits regardless of the gamut container.

CLAIM: “At three bits per pixel, banding is a lot worse with PQ.”

FACT CHECK: Invalid test and part of a demonstrated pattern of misleading or deceptive practices [2]. Lottes intentionally used a bit depth far below the required minimum, guaranteeing severe banding. The HDR standard stipulates 10/12 bits.

CLAIM: “The difference between “SDR” and “HDR” is all artificial marketing. It is quite literally just a OEM artificially limiting the capacity of the display contingent on using the worse non-display-relative HDR signal protocol.”

FACT CHECK: Counterfactual. Firstly, SDR is based on obsolete technology, with standards like BT.1886 designed to mimic the limitations of CRT displays.

Secondly, manufacturers aren’t holding anything back. For instance, in independent testing, in SDR mode, a QD-OLED TV measured 1,024 cd/m² sustained 10% window and 376 cd/m² sustained 100% window [10], demonstrating that modern HDR displays in SDR mode can achieve brightness levels unheard of in any consumer CRT TV.

Takeaway: Technological breakthroughs developed for HDR have raised the peak brightness of displays leading to brighter SDR modes with improved black levels and contrast.

The fact that the Perceptual Quantizer (PQ) is an absolute standard is precisely what makes HDR superior for delivering high-quality, consistent visual experiences across various displays. 

CLAIM: “An ‘SDR’ display with fantastic static contrast with a low APL scene in a dark room is going to look better than an HDR display in daylight that has less real world contrast due to reflection on the screen.”

FACT CHECK: Straw man fallacy. Misrepresents the capabilities and intended use case of the technologies involved.

CLAIM: “If claiming PQ is future ready implies that a gamma display-relative signal somehow isn’t ready, that would be silly, because legacy gamma display relative can target anything.”

FACT CHECK: False. Per ITU-R BT.2390: “A traditional ‘gamma’ power function [allocates] too many code words to very bright regions and not enough to dark regions. This inefficiency was not a serious problem with SDR systems due to their limited dynamic range, but when trying to represent HDR luminance ranges, an improved curve is required [11].”

CONCLUSION

Timothy Lottes’s criticisms of HDR rely on a recurring tactic: constructing tests that violate the standards he claims to evaluate (using 3-bit for a 10-bit standard), admitting to using “fake” data points, and targeting extreme, non- representative scenarios to manufacture negative results.

Footnotes

1. Alessio Palumbo, “The HDR Gaming Interview – Veteran Developer Explains Its Sad State and How He’s Coming to Its Rescue”, Wccftech (Dec. 2, 2025)
2. Lottes admits to fudging data in his 2016 GDC presentation. Describing a key data point illustrating how ambient light destroys contrast, he stated: “Now, I will note that this last one’s kind of a fake one… I did the computation as if I had a 400-nit screen, which is not exactly right.” This admission establishes a disturbing pattern of presenting misleading or invalid test methodologies.
3. HDR10plus.org. Understanding the HDR10 Ecosystem. (2022)
4. Kenneth Chen, Nathan Matsuda, Jon McElvain, Yang Zhao, Thomas Wan, Qi Sun, Alexandre Chapiro. 2025.  What is HDR? Perceptual Impact of Luminance and Contrast in Immersive Displays. In SIGGRAPH ‘25: Proceedings of the Special Interest Group on Computer Graphics and Interactive Techniques Conference. ACM, New York, NY, USA. 
5. Bob Myers, “How are OLED TVs able to produce more contrast than CRT TVs?”, Quora. (ca. 2018); See also AAPM TG18 (2004), Sec. 4.7 “Veiling Glare” and Sec. 4.2 “Display Reflection” for analysis of CRT limitations. 
6. Filippo Tarpini, comment on “Re HDR Filippo Tarpini,” YouTube video. (Dec. 19, 2025)
7. Timothy Lottes, comment on “Re HDR Filippo Tarpini,” YouTube video (Dec. 21, 2025). Gamers with low-end GPUs typically do not have “true” HDR displays.
8. Source: HPA Tech Retreat 2014 – Day 5 report, Q&A on PQ efficiency.
9. HDR10plus.org. Understanding the HDR10 Ecosystem. (2022)
10. Justin Gosselin, Adam Babcock & John Peroramas, “Samsung S95F OLED  TV Review,” Rtngs.com (May 13, 2025)
11. ITU-R BT.2390-12, Clause 5.2 “Design of the PQ non-linearity”

Sources

American Association of Physicists in Medicine (AAPM), Task Group 18, Assessment of Display Performance for Medical Imaging Systems, Preprint Draft (version 10.0), August 26, 2004. Includes analysis of CRT limitations, e.g., veiling glare, phosphor characteristics and reflectivity.

Sec. 4.2 “Display Reflection” describes the specular and diffuse reflections that reduce contrast. Sec. 4.7 “Veiling Glare” describes the internal light scatter (“bloom”) within a display that raises black levels. The section distinguishes between light falling on the display and that inside the display: “Veiling glare is also different from reflection covered in Section 4.2, in that reflection refers to the response of a display device to incident ambient lighting conditions, while glare is an internal display property.”

Timothy Lottes, “Advanced Graphics Techniques Tutorial Day: Advanced Techniques and Optimization of HDR Color Pipelines,” GDC Vault (2016) Presentation slide shows an “HD-ready” CRT TV measured at 302 nits peak. It lists a 158:1 ANSI contrast from a standard checkerboard test, but then presents contrast ratios of 2,500:1 and 30,000:1 from non-standard test patterns (a thin strip and a tiny white rectangle). This demonstrates the selective use of unrealistic, low-APL measurements to exaggerate display capability.

“In the first part, we’re going to look at some display capability from measured examples. And we’re going to start with the past. So, start with the CRT. I’m going to skip ahead. So, this particular CRT is one of mine at home. I just measured it. It’s an “HD-ready” TV. So, it didn’t get very good ANSI contrast – maybe a little over 7 stops. But if you actually start bringing the APL down, say you have an image that’s more in line with what you’d have on say, an HDR image, I started measuring some pretty extreme contrast numbers on the display. I’m just saying here that old technology had the ability to do HDR in some cases. We just never really leveraged it.” Timothy Lottes (AMD), “Advanced Graphics Techniques Tutorial Day: Advanced Techniques and Optimization of HDR Color Pipelines” (2016).