Part I: Project settings
Part II: Color correction
Part III: HDR Palette, project render settings
Part IV: Addendum
From time to time, we’ll provide further clarification about the Resolve Studio 17 HDR workflow and updates in this space.
X-Rite ColorChecker Passport Video
We’ve found that no matter the shooting conditions – whether using daylight-balanced LED lights on the street at night, posing our model in direct sunlight or in the shade – our a7s III footage invariably exhibits the same sickly greenish cast. In the NLE, the vectorscope confirms a pronounced color cast, along with orangish reds and undersaturated cyan. We should add that this occurs in spite of consistently accurate white balance. As each and every project we’ve worked on for the past five months has suffered from this identical deviation, it made little sense to squander away hours fiddling with color wheels and curves when a more scientific approach was already at our disposal – the X-Rite ColorChecker. Having nudged the colors to their respective targets in the vectorscope, the correction could then be saved in the stills gallery of DaVinci Resolve or as a preset in Final Cut Pro and applied to future projects – our modest goal being to have a neutral canvas for creative grading.
If we’ve only talked about lining up the six primary and secondary color chips of the ColorChecker with their corresponding targets on the vectorscope while ignoring saturation entirely, it’s because aligning the colors is paramount, whereas increasing saturation can introduce unwanted noise or artifacts. In general, we think it best to desaturate shadows and highlights to deal with troublesome color casts and to selectively boost saturation in the midtones when desired.
Considering just how effective and simple to use the ColorChecker is, we were bewildered that one never hears of the X-Rite ColorChecker Passport Video vis-à-vis HDR color correction. We reached out to several industry professionals to find out if using a color chart with Rec.709 colorimetry still makes sense in an HDR world, or whether wide color gamut charts were a thing.
Yes the passport should still be fine, you’re just dealing with an expanded dynamic range. So when using auto-balance controls you’d want to set them to a wider gamut like Rec.2020. – Denver Riddle, Colorist, Founder, CGC
Colour charts are not ‘made’ in any colour space. They are later mapped into a specific colour space by the software used. Any colour chart can be mapped into any colour space. – Steve Shaw, CEO, Light Illusion
I’d say it works for all since a colour is a colour regardless of what space it’s represented in, but the numerical values might change depending on the space to represent it, if that makes sense?
The only difference with Rec.2020 say is that it can define colours outside the scope of Rec.709, but anything in Rec.709 still has value in Rec2020.
So I think you’re fine with what you’ve been doing! – Paul Leeming, Cinematographer, Director, Founder, Leeming Lut Pro
Using one is not right or wrong. It’s a tool that helps adjust/normalize captured colors. So, with that in mind if you’ve put colored lighting in or are liking the color light is creating in your image, this will be undone by the color checker re-adjustment. Now, it can also help adjust colored light you don’t like or bring two different cameras’ footage closer to matching.
So it’s a tool. My best suggestion is to never use something until you understand “why” you’re using it. Once you know why you want to use it, it’s easier to do research on whether the tool is good or the right tool for the task…you may be surprised or get creative and solve it for yourself. Hope that helps. – Shane Mario Ruggieri, Sr. Production Engineer, Producer, Colorist at Dolby Laboratories
The X-Rite will be fine for dialing in HDR videos too. The first part of the PQ curve up to 50 IRE is equivalent to SDR. HDR was designed with this logrithmic weighting of data since that’s where most of the important parts of our picture live.
The X-Rite Passport will not help you with the extreme highlights however. This shouldn’t really be an issue unless you are shooting neon signs or are using very narrow band LED lighting. I typically use a luma vs. sat curve to desaturate the highlights past 800 nits anyway.
Also make sure your timeline settings are set for Rec.2020 or the color chart operation will give incorrect values based on Rec.709 timeline settings. Hope this answers your question. – John Daro, Lead Digital Intermediate Colorist, Warner Post Production Creative Services, Warner Media
I’ve used the X-Rite for calibration in HDR work but the workflow for color management in HDR no longer requires things like calibration cards to do anything other than checking exposure or white balance. The only card I carry these days is a grey card, and even then, it’s easy enough to dial in white balance by eye in HDR, so long as your display is a calibrated HDR reference. – Samuel Bilodeau, HDR Consultant, Colorist, & Technologist, Bilodeau Services, LLC
SDR charts are still fine for HDR. HDR/WCG is simply a wider gamut and brightness range than SDR, but SDR test targets still work. A near-0% black and 90% diffuse reflectivity white patch are the same in SDR and HDR; it’s just that instead of putting white at 91% – 100% on an SDR WFM, it’ll go at 100 nits – 200 nits on a PQ WFM, or 73% for BBC-spec HLG, depending on whose standards you’re working towards. As far as color, you’re still matching a ColorChecker by eye anyway, as ColorChecker colors don’t line up on ’scopes in any standardized way.
It’s not possible to make a passive, reflective chart that pushes the boundaries of HDR/WCG since SDR already encompasses what can be done with pigment on a surface. To push past SDR’s range requires an active, backlit chart like a Xyla (in a blacked-out room) while pushing colors needs, again, an active chart like a Northern Lights (and even that isn’t going to hit WCG vector targets precisely since the LEDs don’t line up precisely with REC.2020 primaries and secondaries).
So don’t worry: use your SDR charts as references, and be happy! – Adam Wilt, Software Developer, Engineering Consultant, and Freelance Film & Video Tech