Color Managed workflow vs Non-Color Managed with CSR nodes

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forkbird

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Color Managed workflow vs Non-Color Managed with CSR nodes

PostTue May 04, 2021 7:46 am

Hello,

I'd like to use Film Looks->Rec.709 Kodak LUT at the end of Davinci YRGB Color Managed workflow with Davinci Wide Gamut preset and Rec.709 Gamma 2.4 output color space Project Settings.

To do that right, I need to input Rec.709 as Color Space and Cineon Film Log as gamma into a node with this LUT.

When I set the Color Space Transform node before the LUT node to:

Input color space: use timeline
Input gamma: use timeline
Output color space: use timeline
Output gamma Cineon Film Log

the image didn't seem to look right. It had its highlights blown out.

So, I went back to Project Settings, switched 'Davinci Wide Gamut' preset to 'Custom' which displayed its settings. I learnt that the Timeline Color Space for this preset is Davinci Wide Gamut with Davinci Intermediate gamma.

Then I changed to Davinci YRGB workflow and did the color space transform with nodes from BMPCC4K to DWG/DI and then before the LUT node:

Input color space: Davinci Wide Gamut
Input gamma: Davinci Intermediate
Output color space: use timeline (which was Rec.709 for Davinci YRGB Project Settings)
Output gamma Cineon Film Log

the image looked way better than before.

Questions:
1. Why is it that CSR nodes in Davinci YRGB workflow don't do the same as Project Settings in Davinci YRGB Color Managed workflow?
2. Is there a way to set CSR node in Davinci YRGB Color Managed workflow to feed correct data into the Kodak LUT node?


PS:
The post is getting long but here's another thing I checked out of curiosity:

I switched back to Davinci YRGB Color Managed and instead of 'use timeline' settings I entered DWG as Input color space. As I expected that didn't change anything since it was the same as in the Project Settings with Davinci Wide Gamut settings. But when I changed Input gamma to Davinci Intermediate (again this is what you see in the Project Settings preset) the image turned into a mess. Now, this is something I don't understand totally :)
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shebbe

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Re: Color Managed workflow vs Non-Color Managed with CSR nod

PostTue May 04, 2021 10:21 am

When I was discussing another topic I noticed a discrepancy between color managed and the CST nodes.

You have to manually set the input space and gamma to DWG/Intermediate because Use Timeline takes the Rec.709 Output spaces instead of the Timeline space from the project settings.

Setting it manually should give the same result as non managed.
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shebbe

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Re: Color Managed workflow vs Non-Color Managed with CSR nod

PostTue May 04, 2021 10:49 am

To elaborate, I did a quick test with a RED file.

Nonmanaged:
CST: RWG/Log3G10 -> Rec.709/CineonFilmLog
LUT: Kodak Film Look

Managed:
CST: DWG/Intermediate -> Rec.709/CineonFilmLog
LUT: Kodak Film Look
CST: Rec.709/Gamma 2.4 -> DWG/Intermediate

Maybe you forgot to go back to the timeline space in managed. You have to do this because managed has a "hidden" CST that transforms all to the chosen output space so the node tree has to end in the same space as the timeline space.
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Re: Color Managed workflow vs Non-Color Managed with CSR nod

PostTue May 04, 2021 11:51 am

Thanks a lot for the answer!
It helped :)

I didn't know I need to add yet another CST node after the LUT is applied in the managed workflow to set it back to the Timeline Color Space. That makes sense, though.

I did a comaparison check:

Non-managed:
Input Color Space: BMPCC4K Film Gen 4
Input Gamma: BMPCC4K Film Gen 4
Output Color Space: Rec.709
Output Gamma: Cineon Film Log
->
Kodak LUT

Managed with DWG preset:
Input Color Space: Davinci Wide Gammut
Input Gamma: Davinci Intermediate
Output Color Space: Rec.709
Output Gamma: Cineon Film Log
->
Kodak LUT
->
Input Color Space: Rec.709
Input Gamma: Gamma 2.4
Output Color Space: Davinci Wide Gammut
Output Gamma: Davinci Intermediate

and the waveforms for both are almost identical :)

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