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ACES workflow for color grading cinemaDNG

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Hi,

I wonder what the exact workflow setting I should follow to color grade 14-bit RAW cinemaDNGs in ACES and linear in After Effects primarily, if not in davinci.

This was my previous workflow:
1- Set AE to 32 bpc and working space to rec 709.
2- Import cinemaDNG in AE via adobe camera raw. Select cinelog-C and fix WB, camera profile, remove nosie and sharpen and select correct lens profile. Nothing else.
3- Apply colorIO plugin and set input to cinelog-C and output to arri logC film matrix.
4- adjust exposure, saturation, vibrance, IR pllution etc.

If I want to work with ACES what should be changed in each step of my workflow?

Hi,

Ok so now your set in LOG-c? Cine matrix I thik does not exist anymore…
Have you converted to EXR?
Where are the DNGs coming from? A camera?

Thanks!

Thank you so much!!!

I shot with my canon 5d mark III with 14-bit raw video enabled. Cinverted the footage from RAW to cinemaDNG image sequences.

Ok… There’s some prettu complex things in your workflow that might prevent you from working in ACES.

  • When you convert to from RAW to CineDNG: what are your choices from gamma and gamut? I’m guessing that your probably staying in linear for gamma. But the gamut would be what? Canon Cinema Gamut?

  • The idea here would be to convert your footage to something that ACES “knows”. For example: could you convert to ACEScg using opencolorIO ou for that matter ACEScct? CINELOG-C is not an adequate IDT for ACES. Could you convert from cinelog-c to LOG-C or Slog3/cine? Then you could export from AE in Prores, DPX etc… and use that new file to be correctly identified in ACES.

  • The other option would be to go from linear/camera gamut to linear/ACEScg (via OCIO?). And then export to EXR. But that could make playback hard.

Hopes this helps!

Cheers

I’m attempting to grade my holiday snaps in ACES in Resolve. 5D MkIII CR2s, some of them Dual ISO. I converted them to DNGs with an app called Switch (which uses Adobe DNG Converter for the relevant camera matrix), as this seemed to help in the past when dealing with Magic Lantern Video. I’m using a custom LMT OFX DCTL as well. I’ll report back when they’re finished.

Hi,
I am bumping this thread up because I have the same question and no solution yet. I received DNGs from a camera that does not have an IDT in Resolve for ACES yet. I found an old video where it is shown that Resolve once had an CinemaDNG IDT:

Is there a new workflow that compensates for the lack of a DNG IDT? Thank you!

Hi, can you specify the camera? The cinemaDNG is a format file, what matters for ACES is the encoding and the gamut(in the IDT the camera native).

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CinemaDNG is quite a tricky format to work with due to inconsistency of debayer through different software. We’ve found that the best starting point is to debayer as P3 D60/Linear and then render to OpenEXR. The the files can be imported in Resolve and the correspondent IDT can be applied.

I am sorry but what you are suggesting sounds deeply wrong, or at least not completely specified.
Also, @colorbycontrast asked the right question: what camera was used for shooting? This is where all shoudl be starting from.

Each IDT converts from a camera colorimetry into ACES, not from a file format to another – whereas you are all speaking about converting some file format (DNG) into another (EXR). Also: EXR is another file format: it may or may not encode ACES images, as well as DNG may encode any camera colorimetry.

Without knowing which camera IDT is needed, any suggested workflow may --at best-- work by pure chance only.
Unless the DNG files are already natively in P3, the color pipeline by @Pablo_Garcia seems particularly wrong, since it involves bringing a probably scene-referred camera colorimetry into an output-referred space (P3) and then, somehow, back into ACES (scene-referred). I doubt this would make the workflow any easier, or even facilitate integration with other colorimetries in the same project.

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Hi @chn3d,

If you select ACES(cc/cct) colour science in the Colour Management panel of the Resolve settings, your DNG should be automatically converted (like any other RAW format, Resolve try to bring it to ACES).

This works to the extend that the colorimetric informations in your DNG file are accurate (see the specifications of DNG for more details).

Thanks @walter.arrighetti for your comment. Your notes, on paper are very much correct but I don’t think you have understood the workflow I proposed (that has been tested for several cameras that use DNG as a format and do not have an IDT).
As Chn3d has specified, the camera they used (what ever it is…) does not have an IDT therefore Resolve will debayer it by default as Lin/709. Have you ever tried to grade that? Not to mention in a timeline that contains cameras that do have IDT’s.
Changing to a format that is ACES compliant and encoded as something that ACES understands in this cases is the best workflow we’ve found to be able to use and grade this files in large ACES projects.
Don’t want to get in to an argument here that is not gonna help any of the users. We have tested it and works. That’s all i can say

I think the misunderstanding here is that @walter.arrighetti is assuming that @Pablo_Garcia is taking about converting the DNG to a display-referred, tone-mapped P3 image, and then applying an inverse Output Transform. If I understand correctly, Pablo’s approach is simply to use P3 primaries to create a scene-referred linear image and save that in an EXR.

But, as @remia notes, if the metadata in the DNG is sufficient and correct to decode the image to P3, it will also be sufficient for Resolve to decode directly to AP0. The choice of P3 primaries is arbitrary, and should be unnecessary.

For some DNGs Resolve may read an exposure normalisation gain factor from the metadata, whereas others may simply be have the range from the sensor black level to clipping mapped into the float 0-1 range. In the latter case it may be necessary to apply linear gain to set a reasonable exposure for the image, or use the exposure control in the raw decode parameters.

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I still think It will be nice to know the camera. I mean for example there are some workarounds for the pocket 6k that not involve exporting to EXR etc…

Indeed that will be of much help @colorbycontrast

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All of that relies on proper debayering and metadata documenting, already a database somewhere available on combination of cameras and RAW converters that give proper DNGs?

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