Does Davinci Color Mngt double-convert when using a CST?

I ask because I have an issue trying to go from Rec709 into Davinci Wide Gamut (timeline/working color space) and back to Rec709 without my clip getting muddy and highlights getting flattened out.

My project level management is set to Davinci YRGB, timeline is DWG-intermediate, and output color space is Rec 709/2.4

In my node graph I am using CSTs to move a few different sources into DWG, one of which is Sony Cine2 - and I am treating that as Rec 709 for color space and gamma. If I just bring the clip in it looks fine, but if I round-trip it through CST nodes from R709>DWG>R709 my highlights are getting flattened out and the image gets muddy unless I disable Tone Mapping on the final CST - but I thought I should have that on to account for any out-of-gamut work I might do in the grading between in/out CSTs?

It seems to me that the DWG>R709 tone mapping is maybe happening twice when I use it with the CST - once there, and then again at the project level. Is that true?

If I am using my project level settings as Timeline/DWG and Output/R709, is it even necessary/smart to explicitly do the same round trip at the node level?

You’re not using project level color management, so no. Your output CST should have a forward OOTF. Would be useful to see your other CST from Rec709 to DWG.

Also - why is your Gamma set to Rec709 instead of 2.4 or 2.2? Curious.

What happens if you don't use any CSTs and set both timeline and output to Rec709 Gamma 2.4?

What happens if you don't use any CSTs and set both timeline and output to Rec709 Gamma 2.4?

Presumably OP wants to work in a DWG intermediate timeline color space?

What happens if you don't use any CSTs and set both timeline and output to Rec709 Gamma 2.4?

Presumably OP wants to work in a DWG intermediate timeline color space?

I know, I'm just wondering would he experience any issue and what would result look like.

You’re not using project level color management, so no. Your output CST should have a forward OOTF. Would be useful to see your other CST from Rec709 to DWG.

Also - why is your Gamma set to Rec709 instead of 2.4 or 2.2? Curious.

Thanks for the replies!

Here is the input CST:


re: Rec709 - I have been trying a range of options there trying to get that input/output to match, that is where I landed most recently I guess.

I had thought that PM Color setup should mean it was not affecting my nodes, but I could not figure out why a mapping from Rec>DWG>Rec was flattening things out. If I use FOOTF it does not match at all either. It really seems like this should be simpler so I must be doing something wrong here.

You are correct - I wanted to work in DWG in order to have the bigger color space to grade in, and to be able to use some LUTS that are built for that space.

What happens if you don't use any CSTs and set both timeline and output to Rec709 Gamma 2.4?

Thanks also for the reply.

If I do that I get no change when I add the clip, but then I don't get to work in DWG, which was the main goal for me.

What happens if you don't use any CSTs and set both timeline and output to Rec709 Gamma 2.4?

Thanks also for the reply.

If I do that I get no change when I add the clip, but then I don't get to work in DWG, which was the main goal for me.

Then we know (I am guessing) it is something about your CST settings. Should input CST have tone mapping while yours doesn't?

What happens if you don't use any CSTs and set both timeline and output to Rec709 Gamma 2.4?

Thanks also for the reply.

If I do that I get no change when I add the clip, but then I don't get to work in DWG, which was the main goal for me.

Then we know (I am guessing) it is something about your CST settings. Should input CST have tone mapping while yours doesn't?

I have little doubt I am doing something wrong Here are the options of input/output CST's, and show the result of using the FOOTF vs not on the output CST, and on the input CST, as well as no FOOTF and no tone mapping. That last one is the only one that matches what I get if I don't use any CSTs at all. However, I think then that I am grading in DWG but my gamut might be out of whack. If I leave tone mapping on in the output CST I can crank my output nits to something like 10000 then it matches pretty closely to no CST at all too, but that doesn't make any sense either.

My project settings are still Timeline = DWG intermediate and Output = Rec709/2.4

w/ FOOTF:


w/o FOOTF:


w/o FOOTF and w/o Tone mapping:


w/ FOOTF on input CST and w/ Tonemapping on output CST:

I just tried this myself and you might want to give this a try:

Input CST:
Input Color Space: Rec709
Input Gamma: Rec709
Output Color Space: 'Use timeline' option, do not hardcode 'DWGI'
Output Gamma: 'Use timeline' option, do not hardcode 'DWGI'
Tone mapping: DaVinci
Apply forward OOTF: checked

Output CST:
Input Color Space: 'Use timeline' option, do not hardcode 'DWGI'
Input Gamma: 'Use timeline' option, do not hardcode 'DWGI'
Output Color Space: Rec709
Output Gamma: Gamma 2.4
Tone mapping: DaVinci
Apply forward OOTF: not checked
Apply inverse OOTF: not checked

I just tried this myself and you might want to give this a try:

Input CST:
Input Color Space: Rec709
Input Gamma: Rec709
Output Color Space: 'Use timeline' option, do not hardcode 'DWGI'
Output Gamma: 'Use timeline' option, do not hardcode 'DWGI'
Tone mapping: DaVinci
Apply forward OOTF: checked

Output CST:
Input Color Space: 'Use timeline' option, do not hardcode 'DWGI'
Input Gamma: 'Use timeline' option, do not hardcode 'DWGI'
Output Color Space: Rec709
Output Gamma: Gamma 2.4
Tone mapping: DaVinci
Apply forward OOTF: not checked
Apply inverse OOTF: not checked

That resulted in a slightly brighter/more contrasty image, but fairly close to the non-CST option. Here is the parade - it shows the difference most clearly I think.



Definitely closer, but I don't feel like I am any closer to understanding the logic of the color management here, so not sure how I will deal with varying types of footage

If you don't touch anything, Resolve's default settings are correct. Inverse OOTF on the input, forward OOTF on the output. You might experiment with a gradient to see how the settings affect the image.

Good Luck

Input.png (786.79 KiB) Viewed 1205 times

Output.png (786.44 KiB) Viewed 1205 times

Parity.png (790.89 KiB) Viewed 1205 times

If you don't touch anything, Resolve's default settings are correct. Inverse OOTF on the input, forward OOTF on the output. You might experiment with a gradient to see how the settings affect the image.

Good Luck

Ah - that did it. Inverse OOTF was not something I had tried, or not in the right combination anyway. This produces a net-neutral shift for me. Thanks - this has been driving me nuts!

Good tip about the gradient - I hadn't thought of that but I'll definitely play around with that to help get a better grasp of what's going on.

Thanks again!

Parity.png

How do you get such a nice thick line in waveform when doing gray scale, please? Mine is rather thin and dotted.

If you don't touch anything, Resolve's default settings are correct. Inverse OOTF on the input, forward OOTF on the output.

.. .but isn't file that comes from camera Rec.709 (Scene) on input, not Rec709 Gamma 2.4?

If you don't touch anything, Resolve's default settings are correct. Inverse OOTF on the input, forward OOTF on the output.

Input.png

.. .but isn't file that comes from camera Rec.709 (Scene) on input, not Rec709 Gamma 2.4?

The file is in Sony Cine2, which doesn't have a proper CST. From what I have read and from playing around it is best brought in as Rec709/Rec709 and then a bit of a tone curve to bring up the contrast.

That said, I did not see a Rec709(Scene) in the CST options to try it.

If you don't touch anything, Resolve's default settings are correct. Inverse OOTF on the input, forward OOTF on the output.

Input.png

.. .but isn't file that comes from camera Rec.709 (Scene) on input, not Rec709 Gamma 2.4?

The file is in Sony Cine2, which doesn't have a proper CST. From what I have read and from playing around it is best brought in as Rec709/Rec709 and then a bit of a tone curve to bring up the contrast.

That said, I did not see a Rec709(Scene) in the CST options to try it.

What I'm trying to say is my understanding is that:

1. Files from cameras are in general Rec709 (Scene)
2. In Resolve CST Rec709 Scene means color space Rec709 gamma Rec709

Howard's example uses Gamma 2.4 for input which results in forward OOTF checked but when I use Rec709 for input gamma (to get Rec709 Scene_) forward OOTF does NOT end up checked.

Here are my settings:

Color science: DaVinci YRGB
Timeline color space: DWGI
Output color space: Rec709 Gamma 2.4

CST 1.JPG (270.18 KiB) Viewed 1132 times

CST 2.JPG (270.07 KiB) Viewed 1132 times

CST 3.JPG (273.11 KiB) Viewed 1132 times

The OP was asking why there wasn't parity in the image, garbage in/garbage out. Rec709(scene) is the same as Rec709 2.4 with an OOTF, but there's no need to complicate things. At least one of my cameras records SDR as BT1886 which specifies a 2.4 gamma.

If you want brighter scopes turn up the waveform intensity under scope settings and don't use "video level" scopes, they're usele........Holy Cow! Nevermind. Thanks team Resolve! This almost brought a tear to my eye pattern.

Good Luck

Finally.png (120.46 KiB) Viewed 1103 times

Rec709(scene) is the same as Rec709 2.4 with an OOTF ...

Thank you! So if on input CST with Gamma 2.4 'apply inverse OOTF' is checked that is same as using Rec709 (Scene) with 'apply inverse OOTF' not checked?

If you want better scopes turn up the waveform intensity under scope settings ...

I already have that to the maximum and my waveform line is, as you can see from screenshots I posted above, barely visible

Thank you! So if on input CST with Gamma 2.4 'apply inverse OOTF' is checked that is same as using Rec709 (Scene) with 'apply inverse OOTF' not checked?

That's how it works on my machine.

I already have that to the maximum and my waveform line is, as you can see from screenshots I posted above, barely visible

It might be stuck, have you tried resetting the UI layout under the workspace dropdown? That usually sorts any UI scope bugs.

Good Luck

It might be stuck, have you tried resetting the UI layout under the workspace dropdown? That usually sorts any UI scope bugs.

Thank you, I will give it a try

I have just quickly scanned these posts and maybe I'm missing something major here but I'm wondering why you are bothering to use a CST if the footage is Sony Cine 2 ? That's just a 709 image so just grade the darn thing . What is the value of the CST?

I have just quickly scanned these posts and maybe I'm missing something major here but I'm wondering why you are bothering to use a CST if the footage is Sony Cine 2 ? That's just a 709 image so just grade the darn thing . What is the value of the CST?

To work in DWG intermediate timeline color space. Check out one of Cullen Kelly's recent YouTube videos for reasons why one might do this (jump to about 3min in to where he talks about benefits of working in DWG intermediate):

Add - Actually - he doesn't go into much detail about why he works in DWG intermediate - I just rewatched this, but he does mention that working in a display-referred color space (eg. Rec709) is not preferred. His whole channel is dedicated to talking about the benefits of working in DWG intermediate because of the way it affects the grading controls regardless of the source material and output color space.

I have just quickly scanned these posts and maybe I'm missing something major here but I'm wondering why you are bothering to use a CST if the footage is Sony Cine 2 ? That's just a 709 image so just grade the darn thing . What is the value of the CST?

To work in DWG intermediate timeline color space. Check out one of Cullen Kelly's recent YouTube videos for reasons why one might do this (jump to about 3min in to where he talks about benefits of working in DWG intermediate):

Add - Actually - he doesn't go into much detail about why he works in DWG intermediate - I just rematches this, but he does mention that working in a display-referred color space (eg. Rec709) is not preferred. His whole channel is dedicated to talking about the benefits of working in DWG intermediate because of the way it affects the grading controls regardless of the source material and output color space.

He used DWG partly because every LGG control behaves the same with each camera versus having different results. It's the predictability.

Not just predictability, the offset rolls off nicely at a the top and bottom and behaves closer to photographic exposure. The feel of the controls remains consistent across source footage and output color space, yes.

Thanks, That's interesting and I'm sure it makes sense, though to be honest, if its really a hassle, it's just not hard to use Resolve in 709 space and unless you're really used to the way it works in DWG you can be quite happy with it.

Thanks, That's interesting and I'm sure it makes sense, though to be honest, if its really a hassle, it's just not hard to use Resolve in 709 space and unless you're really used to the way it works in DWG you can be quite happy with it.

They hit it in one actually: I am shifting to DWG for the reasons stated above, and I picked up the workflow from Cullen’s channel.