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Filmic LOG rendering question from a newbie:

Hypothetically, I have a finished scene that I want to use as a background layer for my live action/CG short. However, the live action footage I shot was shot in a generic LOG picture style. My plan was to have my scene also be in LOG, so that I could composite them together in After Effects (my compositor of choice) before finally color correcting/grading the whole thing in Resolve or Premiere. What is the most effective way (if any) to render the scene in a flat LOG picture style for outside composition and grading?

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    $\begingroup$ Save as 16 bit tiff using filmic base contrast, that will be a base2 Log encoded image. $\endgroup$
    – susu
    Apr 24, 2020 at 4:37
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    $\begingroup$ blenderartists.org/t/… $\endgroup$
    – susu
    Apr 24, 2020 at 4:46

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A few notes to set the stage for an answer:

  1. LOG is not a color space. It is a way to encode data (designed to scale large dynamic range Scene Referred data to fit within containers for Display Referred formats (0 to 1)).
  2. Proper compositing should be done using linear data, in a common color- space.
  3. Data from cameras should be linearized first (sometimes called "de-loged"), or converted to scene referred linear value for compositing (as per previous statement).
  4. Blender's data is already linear and using scene referred values.

Attempt to answer

Sure you could create log files, but know that log files have to be converted back to linear for proper compositing. Why work twice, and miss the opportunity to carry the full contents of the render layer created in blender?

As per statement 4. Blender already generates data in a format that is perfectly suited for compositing. Rendered images, with all of their passes (composite, Alpha, Z depth and any number of other passes you want) can be easily stored in OpenEXR multilayer files, and that way the information will never distorted or re-interpreted.

Statement no 3 and 2 carry the information for your compositing workflow

Bring those EXRs files from Blender into Resolve, and composite using Fusion (now part of Resolve). Fusion can deal correctly with linear scene referred data. The linearized (de-logged) footage from your cameras should be easy to integrate that way.

On the settings for the project use "Davinci color managed", set the timeline to use Rec709(scene). In the media tab in Resolve you can set the correct color transform for the footage. Use the "gamut" node, (or OCIO Colorspace nodes) to remove any curves (Log is a "curve") and make sure that the color primaries for gamut are set to sRGB/709.

Once the data from camera and blender is all linear, and in a common color space, you can go ahead and composite, and color grade the result.

To finish, just encode the final images to the delivery format and codec of your choice.

For more detail refer to this link: I have tried to import EXR files to Davinci Resolve with the LUT's

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  • $\begingroup$ Thank you so much. And just to be clear, once both the Blender and camera footage are linearized, I can take them into the compositor of my choice, yes? I only ask because I intend to create 2D hand drawn animated effects that I can’t make in Fusion. $\endgroup$
    – KK Akuoku
    Apr 24, 2020 at 19:44
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    $\begingroup$ Save the images created in blender as EXR, linearizing the video segments can be done wherever you do the compositing, as long as the application you use can work using Linear data. An alternative is to linearize (de-log) the video segments and save as EXR. Then you can bring those into the compositing software of your choice. $\endgroup$
    – susu
    Apr 26, 2020 at 7:04
  • $\begingroup$ What would you recommend as an effective workflow to transform my video footage to EXR? $\endgroup$
    – KK Akuoku
    Apr 27, 2020 at 20:51
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    $\begingroup$ @KKAkuoku To create EXRs from camera footage use Resolve. Set the project to use DaVinci Color Managed, set the input color space to match that of the camera used. Set timeline and Output color space to 709 scene. But it looks to me that for your project you don't really need to create EXRs of your footage. Just create a proxy file to set as background for your drawings. create your drawings as a separate layer and composite all the elements together later. $\endgroup$
    – susu
    Apr 28, 2020 at 18:43

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