Grading SDR First and Trimming for HDR on a Festival Cut

Which version is the master

A festival cut often needs a screening-safe SDR master and, sometimes, one HDR deliverable. The question is which one gets graded first. We lean SDR first and trim up for HDR. That is a working position for this kind of delivery, and it runs against what the vendors document, so it deserves a plain explanation.

The order the vendors assume

Dolby is clear about the sequence. Creating the Dolby Vision master begins with a master HDR grade, made in PQ with a P3 or Rec. 2020 working space and a reference display that peaks at 1,000 nits or more. Analysis runs shot by shot, the colorist adds per-shot trims, and the system tone-maps the master to a 100-nit Rec. 709 SDR version that can be rendered as the SDR deliverable.

The pitch is efficiency: master once instead of building two or three separate grades. That is Dolby's own claim, and for a streaming package with several required deliverables it is a fair one.

It also fits a habit we already have: every cut gets graded twice here, so a second pass is never a surprise. What changes is which pass carries the intent.

Why a festival cut leans SDR first

For us the screening copy is the thing that has to be right, and it is an SDR master. Picture lock, client notes and the sign-off all happen against it. An HDR version, if the festival or a buyer asks for one, is a second deliverable that arrives after the film is already approved.

So we make the approved look the SDR grade. We check it the way we check everything that has to survive a projector, with a theater QC before the cut ships. Then HDR is built from that grade, not the other way around.

What the trim pass actually changes

Going up is less dramatic than it sounds. A Mixing Light walkthrough of Dolby Vision trims on a finished HDR timeline describes the work as mostly small adjustments, made while monitoring the derived 100-nit SDR version, and says the core creative grade is never thrown away and rebuilt. The original SDR grade also stays useful as a creative reference for the trim.

Our order flips the starting point, not the discipline. The SDR look is the intent, the HDR version extends it, and each shot gets checked against the other. This is also why we haven't moved our grade to ACES: we would rather change one thing at a time on a film that has a premiere date.

The cost of going SDR first

The strongest case against us is worth reading. One critic argues that finishing in SDR first undermines HDR: lighting decisions made for SDR ratios limit what HDR can do, and problems show up late, at the first HDR review. The piece cites cinematographer Erik Messerschmidt, ASC, who reported that on a season graded SDR-first the highlights were stretched to fill the HDR range, which gave odd-looking night interiors. On a later season, monitored and finished in HDR, he felt less handcuffed by SDR.

That is an opinion piece resting on two practitioners' experience, and its harshest language is the author's own, not a finding from broad evidence. It still points at a real risk: a film lit and monitored for SDR will have an HDR version that is a stretch of the SDR, not a separate look. We'd rather tell a client that than let the HDR pass pretend to be something else.

A decision rule for the cut

Ask what the HDR is for before the first grading day.

• If HDR is a required deliverable, and the film was shot and monitored with HDR in mind, grade HDR first and derive the SDR. The vendor workflow exists for this case.
• If HDR is an optional extra on a film whose approved look is SDR, grade SDR first, trim up, and tell the client what the HDR version is: an extension of the SDR grade, not a second creative pass.

The next thing to do is practical. Get the full deliverables list from the festival and any buyer in writing, then decide the order.