If you understand color gamuts thoroughly...

[Droning on and on...]

...I have a question for you.

Been studying the issue on line to get a thorough understanding. The question:

A clip taken with a camera calibrated to rec.709, and then played back on a display device calibrated to rec.2020 will look oversaturated, correct? And the opposite, i.e. dull and undersaturated playing rec.2020 source on a rec.709?

Therefore, rec.2020 source can not be graded on a monitor calibrated to the rec.709 standard?

 

[brett8883]

...I have a question for you.

Been studying the issue on line to get a thorough understanding. The question:

A clip taken with a camera calibrated to rec.709, and then played back on a display device calibrated to rec.2020 will look oversaturated, correct? And the opposite, i.e. dull and undersaturated playing rec.2020 source on a rec.709?

Therefore, rec.2020 source can not be graded on a monitor calibrated to the rec.709 standard?

It depends on your system but you’d ideally want to have different calibration profiles for grading SDR vs HDR. Then when you grade HDR you’ll want to use color management and make your output settings to match your display settings exactly. For instance my Mac Book Pro XDR display’s ideal HDR settings are P3 ST 2084, white point D65, and max sustained luminance of 1000 nits for HDR so that’s both the calibration profile I use and that’s also my output settings in my editor for HDR videos.

Using those output settings will add metadata to the video that will tell any display that tries to play my video what my grading environment was and it will then scale the video to the hdr capabilities of the viewing display.

It’s fine to use rec 2020 as a timeline colorspace as long as your output settings match your display capabilities. Most monitors can’t display the full rec 2020 colorspace which is why you don’t necessarily want to use rec 2020 as your output colorspace even if your source material is rec 2020. Now if you really want to use rec. 2020 what you can do is use rec 2020 as your output colorspace but limit the output to P3 color. You essentially want to limit your output settings and therefore your calibration profile to the lowest common denominator of the settings you know your display can produce.

 

[Rchawks]

Huh, lol.

 

[Dave Maine]

Getting a predictable color work flow requires understanding the input work space, the grading workspace, and the delivery workspace. The camera will determine what the input workspace will be - usually Rec709 and a gamma of 2.2 or 2.4.

The editing workspace will be dependent on what your monitor is capable of, and is calibrated to. For HDR work, most monitors are not capable. You will not see the full range of a HDR input on it. It must be capable of 1000 nits of luminance and the 2020 color range.

The device that will be displaying the finished video must have similar specs.

Without this kind of controlled workspace, the final output will be somewhat random.

 

[Dale D]

It depends on your system but you’d ideally want to have different calibration profiles for grading SDR vs HDR. Then when you grade HDR you’ll want to use color management and make your output settings to match your display settings exactly. For instance my Mac Book Pro XDR display’s ideal HDR settings are P3 ST 2084, white point D65, and max sustained luminance of 1000 nits for HDR so that’s both the calibration profile I use and that’s also my output settings in my editor for HDR videos.

Using those output settings will add metadata to the video that will tell any display that tries to play my video what my grading environment was and it will then scale the video to the hdr capabilities of the viewing display.

It’s fine to use rec 2020 as a timeline colorspace as long as your output settings match your display capabilities. Most monitors can’t display the full rec 2020 colorspace which is why you don’t necessarily want to use rec 2020 as your output colorspace even if your source material is rec 2020. Now if you really want to use rec. 2020 what you can do is use rec 2020 as your output colorspace but limit the output to P3 color. You essentially want to limit your output settings and therefore your calibration profile to the lowest common denominator of the settings you know your display can produce.

You lost me on "it depends."

 

[Ralph thompson]

My thoughts, but not an expert.
I think most SW will detect your camera colour space automatically from the metadata if you are working in a color managed environment, eg Davinci Resolve (studio) in a color managed workflow.
Working in large color space on a consumer monitor is not a bad thing to do, you may not be able to see outside the limit capability of your monitor, but you can recover highlights and shadow detail.
But as said, for most of us, you want to output to rec709. so you can see what the vast majority will see their consumer displays.

 

[brett8883]

You lost me on "it depends."

Ok so if you want to edit HDR video and you want to export your edited video as HDR and you want other people with HDR displays to see your videos as close to how you see it on your monitor as possible even though they have different monitors what do you do?

HDR monitors have wildly different capabilities so monitors that conform to standards like HLG, HDR 10, and Dolby Vision have the ability to convert the video I made on my display into a video that can play on your display and look similar, even if your display is wildly different from mine. However, to do this I have to grade my video to a standard that I am comfortable my monitor can display correctly. When I export my video these values will be added as metadata to the video so that when your display plays my video it will make your display conform to the same standard as mine or at least as close to it as possible as your display is able.

First you are going to have to figure out the capabilities of your display and properly calibrate it. Luckily for me Apple makes this pretty easy on their HDR capable displays (XDR displays). It comes with different calibration profiles already built in. The one I will be using is called HDR Video P3-ST 2084.

P3 is the colorspace and ST 2084 is the HDR transfer function or gamma. My display can provide 1000 nits sustained brightness but only with the P3 colorspace and the ST 2084 transfer function and with the white point as D65. If I change any of these settings the max luminance values at the bottom will change to lower values.
Ok so

colorspace: P3
Gamma: ST 2084
White point: D65
Max luminance(brightness): 1000 nits

These are the capabilities of my display that are important to have in the metadata of my videos so my video will display correctly on your screen.

You might ask at this point "the OP asked about rec 2020 not P3 what does this have to do with anything?" Well rec 2020 can't be displayed fully by any remotely reasonable display. Here's the specs for a $3,500 Asus ProArt HDR grading monitor and it can only display 85% of the rec 2020 colorspace and that's a $3,500 display specifically deigned for HDR grading!
We could take our chances with rec. 2020 but we'd have a 15% of messed up colors which is a bit much if you ask me. Instead would be better to use DCI-P3 color which is 98% supported.

Ok so we know the information we need to use and trust me we don't really need to know what it means we just need to know it. So from here how do we make sure this information gets into the metadata of my video so you can view it?

In Resolve we'll go to project preferences and then go to color management. We'd turn on color management and set our options appropriately.
Your color processing mode can be anything you want but you'd preferably want a setting that is at least as big as your footage colorspace. Our HLG footage is rec 2020 HLG so we'll stick with that. The output colorspace is what we really care about. Press save and you are off to the races.

These are things you have to pay attention to and understand if you want to process HDR footage and share it with someone else that likely doesn't have the same display as you and to ensure what you see on your monitor is what your audience will see.

 

[Glenh]

Awesome. Thanks Brett!