Step #1 in HDR grading is defining the project’s ‘speed limit’ and highlight roll-off. Highlights dictate perceptual hierarchy. Shadows are subordinate. SDR-centric grading cripples HDR’s DNA. Start at the top.
1. What does setting a speed limit mean?
Setting a speed limit means defining your target peak brightness (in nits) and highlight roll-off philosophy early on.
2. Why Is Setting A Speed Limit Early On Crucial?
Establishing peak highlight levels early on ensures that brightness serves the story, not the technology.
3. Why do highlights dictate perceptual hierarchy?
Highlights impact the perceptual contrast and tonality of the entire image.
4. Why are shadows subordinate?
Highlights actively limit what we can see in the shadows, not the other way around. The brightest element in a scene sets a “visibility floor” for the darkest shadows.
5. What is SDR-centric grading?
SDR-centric grading refers to the workflow order: first, a full creative grade is established for the SDR version of the content, and then the HDR version is created from that SDR master. It is a ‘bottom-up’ approach.
6. How does SDR-centric grading harm HDR?
SDR-centric grading undercuts one of HDR’s core strengths—preserving relative spatial information that SDR compresses.
Sky UK’s Technical Specification for Delivery of Content Appendix 4: HDR Grading Guidance warns against a bottom-up approach: “To avoid an overly reserved approach… the initial grade should be completed on the HDR version, with the SDR grade being completed afterwards.”
7. What does ‘start at the top’ mean?
Starting at the top means the HDR grade is done first. This is the prevailing industry standard ‘top-down’ approach. An SDR version is then derived from the HDR master.
The Industry Standard Versus A Problematic Alternative
The ‘top-down’ approach is recommended because it makes HDR the primary creative canvas. In contrast, some advocate for a bottom-up approach—a process Cullen Kelly refers to as “lifting the veil”.
Cullen Kelly’s “Lift the Veil” Method
“I like to… start with a standard dynamic range rendering of an image within an HDR container and then to slowly lift the veil… and allow my client to say ‘Oh! I like that,’ or… ‘Wow! That feels like nothing I’ve ever seen before.’” – Cullen Kelly, “Clients love how I use the Creative Potential of HDR” (Colorist Society, Mar. 3, 2025)
Why This Is Suboptimal
Starting with an SDR image inside an HDR container and “lifting the veil” by incrementally increasing the peak luminance is not a widely recognized industry standard workflow for professional HDR color grading. It undermines HDR’s potential, resulting in the “overly reserved” HDR that specifications like Sky UK’s caution against.
For optimal results, the industry recommended practice is unequivocal:
Do I grade HDR first? SDR first? Or do both at the same time?
The HDR should be graded first, followed by a Dolby Vision analysis of the HDR image and a shot-by-shot trim pass of the entire program. It is our experience that – generally speaking – you will get the best results out of both the HDR and the SDR grade if you grade the HDR version first and approach that as the ‘hero grade’. – Netflix. FAQs. “Dolby Vision HDR Mastering Guidelines”
Sources
- J. J. McCann & A. Rizzi. “Veiling glare: the dynamic range limit of HDR images”. Proceedings of SPIE – The International Society for Optical Engineering. (Mar. 2007)
- Vangorp, P., Myszkowski, K., Graf, E., Mantiuk, R. “A Model of Local Adaptation”, ACM Transactions on Graphics (Oct. 2015). Retreived at ACM Digital Library on 11 Dec. 2025
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