HDR grading
Why this lesson
Section titled “Why this lesson”HDR is the biggest gap in free color education, because you can’t fake the reference display and nobody wants to teach the theory without one. So this module is explainer-led: the video fragments give you the vocabulary and the trim mechanics, and the explainer carries the parts they defer — how PQ and HLG actually work, what nits, MaxCLL and MaxFALL mean on a delivery sheet, and what Rec.2100 is. The goal isn’t to make you an HDR finisher today; it’s to make you literate — able to read an HDR spec, grade in a PQ timeline, derive an SDR trim, and be honest about the one thing you can’t shortcut: the display.
Segment: 21:56–27:04 — the HDR palette and targeting an HDR display with a trim passwatch full video
The explainer
Section titled “The explainer”HDR is a bigger box, and the box is measured in nits. SDR grades into roughly 100 nits of peak white in Rec.709. HDR grades into far more headroom — commonly 1000 nits, sometimes 4000. A nit is one candela per square metre, a unit of absolute brightness, and the crucial shift is that HDR is graded in absolute terms: 203 nits isn’t “some percentage of white,” it’s a specific amount of light the display must produce. As the MasterHDR video puts it, HDR removes the very concepts of “white” and “black” — instead you have a deep range of darks below your mid-tone and a wide range of specular brights above it, with no ceiling you’re forced to pin to. Middle grey stays where it always was (around 18%); highlights get room to breathe up into the hundreds and thousands of nits.
PQ vs HLG — two ways to carry the range. The signal has to tell the display how to turn code values back into that many nits, and there are two transfer functions. PQ (Perceptual Quantization, standardized as SMPTE ST.2084, announced 2014) is absolute: a code value maps to a fixed nit level, full stop. Grade to 1000 nits in PQ and “1000 nits” means the same brightness on every correctly set-up display — which is why PQ largely solves the “looks different on every screen” problem and why it underpins HDR10 and Dolby Vision. HLG (Hybrid Log-Gamma, BBC/NHK, 2016) is relative and backward-compatible: its lower range looks correct on an ordinary SDR display, so one broadcast signal serves both. HLG is favoured for live broadcast; PQ dominates cinematic streaming delivery. You grade to one or the other depending on the deliverable.
Rec.2100, Rec.2020, and P3-D65-limited. The container for all this is Rec.2100 — the HDR standard that pairs the wide Rec.2020 gamut (from 3.1’s chromaticity map — a very large triangle) with a PQ or HLG transfer function at 10-bit or 12-bit. But here’s the practical nuance: almost no display can actually fill Rec.2020, so masters are graded P3-D65-limited — colors kept inside the achievable P3 gamut, encoded in a Rec.2020 container. Your delivery spec will say something like “P3-D65 limited, PQ, 1000 nits, Rec.2020 container.” Now you can read every word of it.
MaxCLL and MaxFALL — the metadata that rides along. Static HDR10 delivery carries two numbers so a consumer display knows how to tone-map your grade to its capabilities. MaxCLL (Maximum Content Light Level) is the brightest single pixel anywhere in the program; MaxFALL (Maximum Frame-Average Light Level) is the brightest frame average. A display that peaks at 600 nits reads your MaxCLL of 1000 and rolls your highlights down gracefully rather than clipping blindly. Resolve measures these on export; a QC failure here (wrong or missing MaxCLL/FALL) is a common HDR reject.
Grading in PQ — and the honest compromise. To grade HDR: set your timeline/color management to a scene-referred wide space, set the output to PQ / Rec.2100 at your target nits, and view on a calibrated HDR reference display (an FSI or a consumer OLED in a controlled mode). You grade the same way — balance, contrast, secondaries — but now with headroom, placing speculars and practicals up in the bright range for real impact instead of clipping them. The catch, and it’s non-negotiable: you cannot truly finish HDR without an HDR display. If you don’t have one, grade in a PQ timeline anyway to learn the workflow, use Resolve’s tone-mapping preview to approximate the result on your SDR monitor, and label the output as HDR-simulated — you’re learning the pipeline, not delivering a master. Pretending an SDR laptop can judge 1000-nit highlights is the one lie this course won’t tell you.
Deriving SDR — the trim. Most jobs need both HDR and SDR. Because you graded in a managed pipeline, you re-target the SDR display (output back to Rec.709/Gamma 2.4) and do a trim pass: small per-shot adjustments so the creative intent survives the smaller box — pull the speculars back so they don’t clip, lift a shadow that got lost, retame a color. You don’t re-grade. The Dolby Vision version of this trim, which travels as metadata instead of a second file, is the whole of Lesson 3.7.
- Set a project to a color-managed wide space; set the output to Rec.2100 PQ, 1000 nits (P3-D65 limited). If you have an HDR display, enable HDR monitoring; if not, enable tone-mapping preview and accept it’s an approximation.
- Grade a high-contrast shot with a practical light or window. Push the specular up into the bright range instead of clipping it — feel the headroom PQ gives you.
- Export and read the measured MaxCLL / MaxFALL Resolve reports. Note how a bright frame moves them.
- Derive an SDR trim: flip the output to Rec.709/Gamma 2.4 and do a light per-shot pass — pull speculars back under clipping, rescue any lost shadow. Wipe HDR-intent vs SDR-trim and keep the changes minimal.
- Write one honest sentence about your display: what you could and couldn’t judge.
Terms introduced
Section titled “Terms introduced”Check yourself
What is a nit, and why does it matter in HDR?
What is the core difference between PQ (ST.2084) and HLG?
MaxCLL and MaxFALL are…
You have no HDR display. The honest way to work is…
You can move on when you can… read an HDR delivery spec line by line, explain PQ vs HLG and absolute vs relative, define nits/MaxCLL/MaxFALL, grade in a PQ timeline, derive an SDR trim, and state honestly what your display can and can’t judge.
Go deeper
Section titled “Go deeper”MasterHDRVideo (Samuel Bilodeau) — HDR vocabulary & the bigger box: the clearest free treatment of dynamic range in steps/stops, the data-vs-image distinction, and the history of PQ and HLG. It names the standards but defers their detail to a paid course — the detail your explainer above carries.
Segment: 10:26–19:43 — HDR history and core vocabulary: stops/steps, contrast ratio, nitswatch full video
Segment: 19:43–32:36 — HDR's bigger range vs SDR, and the data-vs-image distinctionwatch full video
- Netflix Partner Help — HDR / Dolby Vision delivery specs (partnerhelp.netflixstudios.com): real, published requirements — nit targets, P3-D65-limited, MaxCLL/MaxFALL expectations. Read a spec you’d actually deliver against.
- Charles Poynton — Gamma FAQ (poynton.ca): the transfer-function grounding under PQ and HLG.
- ACESCentral (acescentral.com): HDR output transforms in a scene-referred pipeline.
The paid path: end-to-end HDR grading — shoot to master, on a real display — is the moat of Mixing Light’s HDR/Dolby Vision series and the MasterHDR full course. This page makes you literate and gets you practising the workflow; those, plus an HDR reference monitor, make you a finisher.
Next up: 3.7 · Dolby Vision & derived deliverables — the metadata trim system that derives SDR from your HDR grade without a second file.