Hybrid Log Gamma vs PQ Gamma grades Resolve 17

I’m new to grading in HDR so appreciate any advice how to manage this:

As part of becoming familiar with grading in HDR, I have shot the same scene in BRAW and ProRes using Gen 5 LUTs. Applying the SDR LUTs with Dynamic Range Film I saw that the PQ Gamma LUT seemed to give a good starting place for grading right away. However applying the Hybrid Log Gamma is quite different. HLG does a great job with the brightest parts of the scene, but things that generally look average brightness and darker all show very much darker on the screen compared to the PQ Gamma.

I have my Apple Display XDR set to the P3-D65 ST.2084 reference mode and I grade being guided by the Resolve scopes with the project
timeline colour space gamut P3-D65,
gamma Rec.2100 ST2074 and
Dolby Vision 4 set to 1000nit,P3,D65,ST.2084,Full

With these settings I can adjust the Colour HDR wheels to match the HLG grade with PQ but it’s not easy.

I have noticed if I set the gamma to Rec.2100 HLG
(and then also set Dolby Vision to 1000nit,BT.2020,D65,ST.2084,Full)
I get a brighter grade exceeding 1000nits using the HLG setting instead of ST.2084 but I want to stay with ST.2084.

Can anyone comment on the dramatic difference in luminance of the average and darker levels in HLG versus PQ gamma? Is that typical and nothing to be concerned about?

Am I using the correct project settings for Colour Management to deliver for viewing on a new LG OLED G1 65” 4K television that supports P3?

HLG is a hybrid. It's meant to be able to be displayed as-is on an SDR device and still look reasonable. Only the top end is log-like. So your description of how it looks makes sense. But I've only read about it.

Thanks, I should also mention that I haven’t delivered any HDR videos yet; just noting when working on the Resolve Colour page that the luminance curve is so different for HLG than PQ. I’d like to deliver HLG for the reason you cited.

HLG, as mentioned, is hybrid. The first 100 nits is mapped in SDR and anything above that is HDR.

Which HDR format you will deliver will depend on the broadcaster/streamer. In the US, PQ is the "standard". Dolby Vision and HDR10 being the 2 most popular.
I do not know any that accepts HLG. If I am not mistaken, HLG was formed by the BBC and Japanese collaboration.

Thank you for your comment. Sounds like I can focus my attention on PQ which didn’t present any challenge. That’s where I can start. But good I became familiar with HLG in case there’s ever a need. I think the LG OLED G1 television can accept either.

The more I’ve been comparing PQ and HLG grades, I’m comfortable with the results from either based on the scopes and the expanded grading tools for HDR in DaVinci Resolve. When I’m dialing in a HLG grade, I try to make sure the scene was well lit to begin with and then be careful what information is placed in the first 50 nits, then 50-90 nits, then 90-100 nits, and lastly over 100 nits. When grading PQ, I also watch the content at 100-203 nits. Even though most of the content is under 100 nits, having those brighter bits is important to the impact of the final image. I’ve also been watching films to see how they look on an SDR 100-nit screen and an HDR 1000-nit screen to note what has been altered.

When I began, it was confusing in part because I had made assumptions that weren’t right. I’d say getting that order of magnitude of extra light seems to be associated with an order of magnitude of extra effort but the results are worth it. Having the HDR LUTs in camera (and applied in Resolve Colour Managed) gives a good starting point. Can’t wait to grade for the LG OLED.

I speak only for PQ, being the format required by Netflix and Amazon from us those days.

1) the normal log of a camera represent the photography well. There is no need for Mumbo-Jumbo mapping
2) ideally i set a “nit target” for my project (say 1000 for exercise) and split in main tonal range and highlight mapping
3) i ideally extract either with a LOOK/LUT/Curves, whatever fit, the 7-8 stops of good exposure from tyhe log an map it into the final curve between black nit level and 95isc of the intended target
4) recover about a stop of original highlights and map that I teh remaining 5isc%.

Then you’re good to grade.

The main curve is a “s” curve with 7ish stop fo linear output and toe/shoulder, where the shoulder is expanded to map the extra highlights.

Is not different than color for projection or SDR, instead of 100nits you have a virtual display that can do “X” nits and the added definition in the highlights and shadow allow you to map a bit more into that.

If you want to see the concept in action watch in HDR “homecoming” (amazon), “the old guard” (netflix), “Bliss” (Amazon) and so forth.

Those project all have a global “look” that target an intended nit level with a single curve and colored underneath.

Thank you so much, Walter. I must say your first point gave me a chuckle! Just to be sure I understand that first point, I hope I’m correct then in saying there’s no requirement to begin a PQ grade with a PQ LUT in camera or in RCM. Will do the right thing as you outline in the other points.

I’m making a note of your message for future reference and will give this a go soon.

Thank you so much, Walter. I must say your first point gave me a chuckle! Just to be sure I understand that first point, I hope I’m correct then in saying there’s no requirement to begin a PQ grade with a PQ LUT in camera or in RCM. Will do the right thing as you outline in the other points.

I’m making a note of your message for future reference and will give this a go soon.

Correct, in my point of view, a normal "log" developed raw is a valid and good starting point

HLG is a hybrid. It's meant to be able to be displayed as-is on an SDR device and still look reasonable. Only the top end is log-like. So your description of how it looks makes sense. But I've only read about it.

This is theory.
In practice HLG displayed as SDR as is (without any transformation) doesn't really look acceptable and I don't think anyone does it this way.

HLG, as mentioned, is hybrid. The first 100 nits is mapped in SDR and anything above that is HDR.

Which HDR format you will deliver will depend on the broadcaster/streamer. In the US, PQ is the "standard". Dolby Vision and HDR10 being the 2 most popular.
I do not know any that accepts HLG. If I am not mistaken, HLG was formed by the BBC and Japanese collaboration.

HLG is for broadcast. You can shoot and transmit as HLG on the go. It’s a ‘final’ transmission format. In theory you don’t really grade HLG recorded sources. You may correct it a bit ( like you do for Rec.709).
PQ is rather different. You shoot in some ‘most camera optimal format’ and then creat PQ master from it. It’s more a mastering format which needs more work to get final desired look.

Okay I followed the instructions to just grade (some CinemaDNG lossless footage from the UM4.6K) from my original clips without aid of a PQ LUT but respectful of the limits of PQ and a 1000-nit screen. Then I did another grade beginning with a PQ Gamma LUT doing the initial heavy lifting to begin the grade.

I must admit the hand-cranked grade has mostly better colour and saturation so it really looks good with three caveats:

I have a day-glow green bicycle jacket that looks too yellow in the hand-cranked grade using only primary colour wheels—the green is more realistic using the PQ Gamma LUT.

I’m shooting interior and looking to a bright exterior and there is a purple shift where one vertical dark window divider (whatever that dark post-thing is called that makes it look like four windows when it’s only one)—on the PQ Gamma LUT the posts are perfectly dark.

There’s a bookcase partially in the shadow and when I raise the brightness, part of the wood tends to show some redness—in the PQ Gamma version there’s no redness.

I might be able to cure those issues hand-cranked, but so far I haven’t completely been successful. And I likely can give the PQ Gamma LUT version some additional work to give it a more pleasing warmer look keeping the green but without the purple or red erupting.

Very interesting to do a direct comparison of techniques.

Not sure if I understand your original problem.
PQ and HLG ‘gammas’ are very different and you can’t just swap one to another.
As far as I know you set project to HLG or PQ depending on your need and grade.
If you need both than it will always need correction regardless which you start with.

Of course in both cases you need correct monitoring. When it comes to HLG with LG I’m not sure if BM cards can pass HLG flagging. Does your LG says you are monitoring HLG ?

The fundamental difference between HLG and PQ for delivery is that HLG is relative whereas PQ is absolute.

The following is a good read if anyone is interested in some detail: https://downloads.bbc.co.uk/rd/pubs/pap ... TV_FAQ.pdf


Any reason why you're using LUTs and not going down the Color Managed workflow path?

I have an Youtube Channel and I started to upload my episodes in PQ HDR, using ACES cct color management in Resolve. I have tried the workflow in HLG, but I had much more better results with PQ. HLG came up with very different results across different devices. Maybe the Youtube SDR conversion works better with PQ.

It is not super graded, it is very natural actually, but I feel like it stand out next to the other YouTube videos, especially at moments when is brighter than the YouTube interface. I am still learning to grade in HDR, so a lot of room to improve, but I already like much more the results I got now than with SDR uploading, just for the 10bit playback it already worth it.

... When it comes to HLG with LG I’m not sure if BM cards can pass HLG flagging. Does your LG says you are monitoring HLG ?

Yes, there is tagging in Resolve 17 under Video / Advanced Settings / Gamma Tag: Rec.2100 HLG and Rec.2100 HLG (Scene).

I’m waiting for the release of the LG OLED G1 65” 4K television to find out if I’m doing this correctly! So at this time I just grade with the HDR 1000-nit scopes and preview on the Pro Display XDR with P3-ST 2084. Not ideal but I just want to be in the ballpark now.

... Any reason why you're using LUTs and not going down the Color Managed workflow path?

I’m using LUTs at the moment to give me a starting point, but have switched to Resolve Colour Managed recently. The LUTs just give a starting point for a grade and I usually apply them in my camera/monitor to guide exposure. The sample screenshots I posted alas were shot that day for another purpose entirely where they didn’t have to look good; I was only using them in this thread to illustrate the difference between the LUT and hand-cranking a quick grade of a challenging shot (challenging because it’s a bad shot with wide variation in stops including underexposed areas).

I have an Youtube Channel and I started to upload my episodes in PQ HDR, using ACES cct color management in Resolve. I have tried the workflow in HLG, but I had much more better results with PQ. HLG came up with very different results across different devices. Maybe the Youtube SDR conversion works better with PQ.

It is not super graded, it is very natural actually, but I feel like it stand out next to the other YouTube videos, especially at moments when is brighter than the YouTube interface. I am still learning to grade in HDR, so a lot of room to improve, but I already like much more the results I got now than with SDR uploading, just for the 10bit playback it already worth it.

Adriano, I didn’t think Resolve 17 was ready with all the HDR options for ACES. I used to use ACES for SDR. Looks like I should take another look at ACEScct. How did you get HDR out of ACEScct in Resolve 17?

There are arguments for using either PQ or HLG so I’m still learning both. Your work is an excellent example though of the HDR approach producing lovely results in SDR when uploaded.

Thank You! Those are my settings. I hope it helps you.

... When it comes to HLG with LG I’m not sure if BM cards can pass HLG flagging. Does your LG says you are monitoring HLG ?

Yes, there is tagging in Resolve 17 under Video / Advanced Settings / Gamma Tag: Rec.2100 HLG and Rec.2100 HLG (Scene).

I’m waiting for the release of the LG OLED G1 65” 4K television to find out if I’m doing this correctly! So at this time I just grade with the HDR 1000-nit scopes and preview on the Pro Display XDR with P3-ST 2084. Not ideal but I just want to be in the ballpark now.

If you use HLG project in Resolve and set Apple screen to HLG preset then this is fine.
If you use HDR PQ preset in monitor then this is sooo wrong.
Your monitor setting has to follow Resolve setup.

I’m not talking about project’s color space setup, but Resolve sending correct flag over BM card HDMI to your screen. In the past only PQ was supported. Not sure if latest Resolve flags HDMI signal for HLG in case of HLG based project. HDMI flagging is a separate thing. In order to tell if it works you need to check if TV switches to HLG mode.

Yes, agree. Thanks, Andrew.

I’d be doing two different grades and renders for HDR PQ and HLG and hopefully a trim would not be needed for a SDR television playing the HLG. I am assuming a PQ conversion to SDR deliverable can be handled by render parameters and tags, but the project may need tweaking of the grade if my PQ grade didn’t play by the rules. I understand strictly following all the rules isn’t necessary if the PQ will only be played on a HDR television supporting PQ.

Do you feel my assumptions are valid or would you also tweak the HDR HLG for rendering a version for playing SDR HLG always anyway?

If you use HLG project in Resolve and set Apple screen to HLG preset then this is fine.
If you use HDR PQ preset in monitor then this is sooo wrong.
Your monitor setting has to follow Resolve setup.

I’m not talking about project’s color space setup, but Resolve sending correct flag over BM card HDMI to your screen. In the past only PQ was supported. Not sure if latest Resolve flags HDMI signal for HLG in case of HLG based project...

My plans may need amending as the only true HDR setting on the Pro Display XDR is P3 D65 ST2084. Is that only useful for doing PQ grades in Resolve or can it also be used for HLG previews? I’ll be relying on the LG OLED G1 in the future.

Apple has other HDR settings up to 1600 nits but they’re not standard so I don’t use them.

HLG looking acceptable when playing as is on SDR TV is more a theory than real thing. From what I've seen it's not really looking acceptable (it's dull and too dark), but not that much work is needed to make it looking ok as SDR. Simple Resolve conversion with tone mapping+few tweaks here and there should be easily enough. I think there are some BBC LUTs floating around which convert HLG to SDR, but those are always a compromise compared to what you can do in Resolve.

If you use HLG project in Resolve and set Apple screen to HLG preset then this is fine.
If you use HDR PQ preset in monitor then this is sooo wrong.
Your monitor setting has to follow Resolve setup.

I’m not talking about project’s color space setup, but Resolve sending correct flag over BM card HDMI to your screen. In the past only PQ was supported. Not sure if latest Resolve flags HDMI signal for HLG in case of HLG based project...

My plans may need amending as the only true HDR setting on the Pro Display XDR is P3 D65 ST2084. Is that only useful for doing PQ grades in Resolve or can it also be used for HLG previews? I’ll be relying on the LG OLED G1 in the future.

Apple has other HDR settings up to 1600 nits but they’re not standard so I don’t use them.

Hmm...Apple screen has no HLG preset, so this is not good.
Using PQ preset for HLG graded content in my opinion is totally wrong.

Those 1600 nits are about max capability of Apple screen, so this is rather for custom viewings.
Nothing stops you to grade to 1600 nits on Apple screen, but this is somehow custom master as not many displays can do 1600nits and this is bit random value (although still correct). Most screens later would have to map this to 1000nits, so it's about pointless. It's purely for Apple screen or any other which can do 1600nits peak or more (which are not many out there). In pro world stick to 1000nits.

Once you have LG you need to test if HLG project in Resolve triggers HLG mode in LG TV using BM card. If not then you would need to buy one of the HDFury boxes (extra eg. 100$+) to inject HLG signalling to HDMI, so LG is put in HLG mode. Other way is setting LG TV to HLG mode using service menu (I think people now figure out how to do it). There is no user setting in TV to do so in case of LG.

One more time- rule is simple. Monitoring needs to match your Resolve project setting. Grading to HLG with TV set to HDR PQ mode is nonsense.

...

One more time- rule is simple. Monitoring needs to match your Resolve project setting. Grading to HLG with TV set to HDR PQ mode is nonsense.

Thanks again. I’ll let HLG ambitions go for now and concentrate on PQ. I think I had a misconception related to Rec.2100 supporting both PQ and HLG which is true, but it doesn’t help me preview HLG on my Pro Display XDR as I thought might be feasible. That might explain why HLG didn’t look right to me!

When I was reading about this HDR stuff, I came across comments that the new Panasonic cameras (like S1 family) support HLG and Canon cameras (like the R) family support PQ. So I’m not going to look further into the S1 family either. I’d like to know what the Sigma fp supports and what the unreleased Sigma fp L supports for their HDR video. I’ll address that Sigma question in another thread, but if someone knows the answer feel free to mention it here.

When I was reading about this HDR stuff, I came across comments that the new Panasonic cameras (like S1 family) support HLG and Canon cameras (like the R) family support PQ. So I’m not going to look further into the S1 family either.

I don't think it works that way. These are all HDR cameras, in the sense that they capture data beyond the 709 color space, and they don't insist on recording in a 709 color space. I think "support" here only means, directly out of the camera. The log or raw files are agnostic; data or potential data would be determined by the usual suspects: bit rate, data rate, color sampling, sensor dynamic range, etc., rather than, say, an "HLG" setting on the camera, which you'd never use anyway if you anticipated doing post-production.

iPhone 12 records HLG with Dolby metadata on top of it. If you play file on device with Dolby then this extra metadata is used. If your device has no Dolby then you see HLG. In both cases it’s just some HDR footage recorded in the way that it’s ready for final viewing. Dolby just adds extra metadata calculated during recording to improve final result.

Overall every modern decent camera can record HDR footage. Difference is the form of this recording: either something ready to display ( eg. HLG) or other form of data ( most likely LOG based) which you then work on and export as final video ( can be also HLG but also HDR PQ etc). With HDR we have now 2 forms of final data: Rec.709 SDR or HLG HDR. Both meant to be final videos, but we know that they can be still adjusted in some amount ( like we keep doing with Rec.709 ). HLG for HDR is the same as Rec.709 for SDR. PQ is different as it’s not recording format, but mastering, which needs creative work.

... HLG for HDR is the same as Rec.709 for SDR. PQ is different as it’s not recording format, but mastering, which needs creative work.

Thanks, Andrew; that helps simply things. How strange that Apple hasn’t thought they should provide a HLG ‘reference mode’ for the Pro Display XDR. I imagine it will be part of a firmware update someday. If you know what you’re doing you could create a custom reference mode and call it HLG, but I can barely tie my shoes so I wouldn’t attempt to define a reference mode from scratch.

When I was reading about this HDR stuff, I came across comments that the new Panasonic cameras (like S1 family) support HLG and Canon cameras (like the R) family support PQ. So I’m not going to look further into the S1 family either.

I don't think it works that way. These are all HDR cameras, in the sense that they capture data beyond the 709 color space, and they don't insist on recording in a 709 color space. I think "support" here only means, directly out of the camera. The log or raw files are agnostic...

Agree, John; thanks for pointing that out to me.

I read the entire specs for the Sigma fp and the only time they mention HDR it’s in that original but dated still photo meme of sandwiching multiple exposures to create a pleasing higher dynamic range image. I’d basically always be recording 12-bit CinemaDNG from the USB-C connector (even while the camera is on a gimbal) to a SSD or recording 12-bit raw via HDMI locked down and tethered to a BMVA12G7. Either way the file will support Rec.2020 data. End of research.

Thank you for everyone’s comments on this topic. I feel more confident that I understand HDR grading now. I’ll come back here when I have some experience with the LG OLED G1 Evo.

So looking forward to that in the spring if I can afford to secure a unit. The prices in Canadian dollars may not be known yet but from what I’ve seen for the prices for last year’s units, it could be frightening. Oh well, no pain, no gain. And at least the Canadian looney is getting stronger instead of weaker.

Monitor itself supports HLG incoming signal based on their info. The way how HLG works means it always adapts to display capabilities, so same HLG signal can be displayed on 1000nits master, 1600 nits, up to 4K nits.
I assume if you had signal flagged as HLG and going into Apple screen then it most likely will internally switch to proper HLG mode, like LG TVs do.
I'm not sure how this plays with fact that there is no provided HLG reference preset. There is no way you can set same PQ preset and expect HLG graded signal to look correct. It makes no sense. If anything you may want to be in monitor native mode.

You can do own testing. Try any properly HLG flagged file (should be some on the internet) to play with QT X and watch what happens on the monitor. Then try swapping monitor modes and see if they affect in any way what you see. HLG file should say this:

Screenshot 2021-03-14 at 21.03.54.png (34.34 KiB) Viewed 9599 times

Key value is 18 which means HLG gamma.

Thank you for everyone’s comments on this topic. I feel more confident that I understand HDR grading now. I’ll come back here when I have some experience with the LG OLED G1 Evo.

So looking forward to that in the spring if I can afford to secure a unit. The prices in Canadian dollars may not be known yet but from what I’ve seen for the prices for last year’s units, it could be frightening. Oh well, no pain, no gain. And at least the Canadian looney is getting stronger instead of weaker.

There is really no difference with HDR grading compared to SDR.
You set project correctly, you add calibrated/verified monitoring.
Interpret any incoming footage as per camera brand or just work with 'pure LOG' data. Grade, watch what you see and done:)

Monitor itself supports HLG incoming signal based on their info. The way how HLG works means it always adapts to display capabilities, so same HLG signal can be displayed on 1000nits master, 1600 nits, up to 4K nits.
I assume if you had signal flagged as HLG and going into Apple screen then it most likely will internally switch to proper HLG mode, like LG TVs do.
I'm not sure how this plays with fact that there is no provided HLG reference preset. There is no way you can set same PQ preset and expect HLG graded signal to look correct. It makes no sense. If anything you may want to be in monitor native mode.

You can do own testing. Try any properly HLG flagged file (should be some on the internet) to play with QT X and watch what happens on the monitor. Then try swapping monitor modes and see if they affect in any way what you see. HLG file should say this:

Screenshot 2021-03-14 at 21.03.54.png

Yes that occurred to me a few days ago but I didn’t think it was a legit test; however HLG should adjust as you point out and it’s easy to do. Might be good to go to the P3-1600nits and the P3-500 nits mode to view my tests of HLG grading. I haven’t played with the reference modes for P3-DCI and P3-D65 either. No harm in trying.

Well that did the trick! My HLG grade looks much better at the 1600nits and 500nits and P3-D65; and the day-glow green jacket has more green than yellow as it should. That was a very good suggestion; thanks for sticking with me on this adventure., Andrew. And big thanks to Walter Volpatto that gave me offline advice on the grading as well.

HLG is no near to be found in advanced setting etc. on XDR, yet they say it's supported.
I think it's supported through apple color engine and screen need to be in its native mode. Then HLG is mapped to its 1600 nits capabilities.

Now- if you want HLG 'external' signal then I'm not sure how it handles it. Not sure if HLG flagging is preserved by eg. BM's Teranex Mini SDI to DisplayPort 8K HDR. If so this may trigger HLG 'processing', but I'm not sure at all. There is also no mention what exact mode screen should be for HLG viewing. It's a bit grey area.

You can do testing as you mentioned.
Another test is grade something in PQ with screen set to PQ preset.
Then convert it in Resolve to HLG with color space transformation and export HLG flagged file.
Play this with with QTX setting monitor to different modes and see if anything shows about same image as original PQ grade (in PQ preset).

All of this means that there may be no easy way to display HLG out of Resolve GUI preview. Or maybe there is easy way and if Resolve project is set to HLG then OSX color engine sees it and trigger HLG processing. Then it's the best to have monitor in its native mode.

Well that did the trick! My HLG grade looks much better at the 1600nits and 500nits and P3-D65; and the day-glow green jacket has more green than yellow as it should. That was a very good suggestion; thanks for sticking with me on this adventure., Andrew. And big thanks to Walter Volpatto that gave me offline advice on the grading as well.

Cool. It definitely makes more sense using native mode than PQ for sure.

Once you have LG then you can do HLG test.
Grade (assuming monitoring on LG works fine) some HLG master and export it as h265 HLG flagged.
Then with the same project go to export and just change Gamma Tag in export advanced setting to 2.4 and export SDR flagged file.
Play both files in LG internal player.
This will show you how acceptable HLG file look on SDR playback without any adjustments.
I assume this can depend on grading and how your data in distributed across whole single range. If HLG curve starts be different at about 70% of the signal then this will be deciding point for SDR look. If a lot of data is above this then SDR playback will be dull I assume. If not then it may look acceptable.

...
Another test is grade something in PQ with screen set to PQ preset.
Then convert it in Resolve to HLG with color space transformation and export HLG flagged file.
Play this with with QTX setting monitor to different modes and see if anything shows about same image as original PQ grade (in PQ preset)...
Then it's the best to have monitor in its native mode.

I did a few different tests and the best result was grading everything in PQ with the Broadcast Rec.2020 PQv4 LUT, using the CST with Gamma set to Rec.2100 HLG (Scene),
tagging the deliverable with Rec.2100 HLG (Scene).

Didn’t really like that result. It made some areas brighter under the mantle but not nice.

My best result was doing a grade for HLG with Rec.2020 PQ LUT,
using the CST Rec.2100 HLG (Scene),
Primaries with some Offset, but dark,

Tag Rec.2100 HLG (Scene).

Displaying that in the 1600nits native screen of the Pro Display XDR gives me a low lit image in the render that doesn’t have all that dark crushed area under the fireplace mantle.

Oh, man.... It looks like a thoroughly haphazard workflow, to achieve, in one instance, an acceptable monitoring result. How could you ever hope to deliver a program to a third party with such mixed methods?

That was an exercise to see if I could take a PQ Gamma grade and easily make an HLG deliverable from the same grade. Well you’ve hit the nail on the head; it’s far from trivial if your clip is a difficult situation with interior and exterior light. I’m going to try a well-exposed clip soon and hope that’s much less work. But I found it much easier to grade for PQ and I think that’s what I’ll concentrate on going forward. Thanks for the feedback, John.

I did a few different tests and the best result was grading everything in PQ with the Broadcast Rec.2020 PQv4 LUT, using the CST with Gamma set to Rec.2100 HLG (Scene),
tagging the deliverable with Rec.2100 HLG (Scene).

Didn’t really like that result. It made some areas brighter under the mantle but not nice.

My best result was doing a grade for HLG with Rec.2020 PQ LUT,
using the CST Rec.2100 HLG (Scene),
Primaries with some Offset, but dark,

Tag Rec.2100 HLG (Scene).

Displaying that in the 1600nits native screen of the Pro Display XDR gives me a low lit image in the render that doesn’t have all that dark crushed area under the fireplace mantle.

If you're delivering for HDR, you really should be using either of the following color managed workflows:

RCM with DaVinci Wide Gamut preset
or
ACEScc/ACEScct

then set output to either HLG or PQ (ST2084) at the desired NIT level.


Also, as a footnote, Resolve 17 has messed up something with HLG (Scene). I haven't had the time to look into it, but it's not the same as from Resolve 16 which had the correct behavior.

I’ll take a look at the settings for the ACEScct workflow that Adriano provided earlier. And I can avoid (Scene) for now if you feel it’s problematic. Thanks.

I did a few different tests and the best result was grading everything in PQ with the Broadcast Rec.2020 PQv4 LUT, using the CST with Gamma set to Rec.2100 HLG (Scene),
tagging the deliverable with Rec.2100 HLG (Scene).

Didn’t really like that result. It made some areas brighter under the mantle but not nice.

My best result was doing a grade for HLG with Rec.2020 PQ LUT,
using the CST Rec.2100 HLG (Scene),
Primaries with some Offset, but dark,

Tag Rec.2100 HLG (Scene).

Displaying that in the 1600nits native screen of the Pro Display XDR gives me a low lit image in the render that doesn’t have all that dark crushed area under the fireplace mantle.

If you're delivering for HDR, you really should be using either of the following color managed workflows:

RCM with DaVinci Wide Gamut preset
or
ACEScc/ACEScct

then set output to either HLG or PQ (ST2084) at the desired NIT level.


Also, as a footnote, Resolve 17 has messed up something with HLG (Scene). I haven't had the time to look into it, but it's not the same as from Resolve 16 which had the correct behavior.

No you don't if you know what to do.

Fair point Walter. That would fall in the "Advanced Users" category

Thank You! Those are my settings. I hope it helps you.

I followed your settings with only minor changes to deliver P3-D65 rather than Rec.2020 Gamut. First used your PQ settings with a few Colour Wheel adjustments and then changed the settings to reflect HLG. The only grade change was a small change to one HDR Colour Wheel so that was easy and very fast to go from a PQ to HLG render using ACEScct.

Perhaps all I really needed were the project settings and deliver changes to make the switch so a minute to deliver HLG after PQ.

Nice!
Good to know!

If you use HLG project in Resolve and set Apple screen to HLG preset then this is fine.
If you use HDR PQ preset in monitor then this is sooo wrong.
Your monitor setting has to follow Resolve setup.

I’m not talking about project’s color space setup, but Resolve sending correct flag over BM card HDMI to your screen. In the past only PQ was supported. Not sure if latest Resolve flags HDMI signal for HLG in case of HLG based project...

Once you have LG you need to test if HLG project in Resolve triggers HLG mode in LG TV using BM card. If not then you would need to buy one of the HDFury boxes (extra eg. 100$+) to inject HLG signalling to HDMI, so LG is put in HLG mode. Other way is setting LG TV to HLG mode using service menu (I think people now figure out how to do it). There is no user setting in TV to do so in case of LG.

One more time- rule is simple. Monitoring needs to match your Resolve project setting. Grading to HLG with TV set to HDR PQ mode is nonsense.

I can confirm that the LG C9 and CX receive the HDMI flag for HLG and HDR10 from Resolve when using BMD Mini 4K Thunderbolt 3 Capture and Playback interface.
There is no need to set the HDR format manually in the TV.
Resolve automatically sends the selected format.

Thank you, Willian.