Octane C4D ACEScg EXR RGB colours

Hi, I have been using ACES within Octane C4D (not sure how implemented it is in Octane as they are always updating builds) and DaVinci Resolve, outputting 32bit exr renders with Octane OCIO ACEScg and imported into DaVinci Resolve for Stills and animations. I have set lighting to texture and float to maintain neutral colour lighting environment. ACES OCIO is configured in Octane as per the manual. My textures/design images are sRGB (C4D internal linearisation).

However the colours in the render do not match, i.e., the sRGB red maybe 255, 40, 40 but I get something like 243, 30, 0.

Am I doing something wrong? Why are the colours not matching? If I view in HD sRGB the values are closer but I want a ACEScg tagged EXR, if that makes sense.

Thanks in advance for any input, Chris

Hi Chris, can you share some screenshots to see your texture, 3D scene and the output?

It is hard to imagine what exactly is happening.



Hi Daniel, thanks for responding.

Here are some images of my workflow. I would expect (my intention under neutral light colours and correct exposure, hence the 128, 128, 128 swatch) my final output render colour values to match my original image.

Images show: Photoshop image (could be a brand logo with colours) > setup in Octane and output > import in DaVinci resolve (the import values are the same as the Octane live viewer so i guess we can kinda ignore that step for now).

I put a grey in 128, 128, 128 which it seems to handle well, but as colour values move into the brighter and darker values they shift (not uniformly). No colours reach 255 (I am guessing this is a role off and maybe ACEScg is not the best solution for this type of work).

Input and output values
255, 40, 40 > 233, 40,31
100, 128, 255 > 100, 129, 221
128, 128, 128 > 128, 128, 128

Octane Config: OCIO config 1.2 > ACES 2065-1
Octane Camera Imager: ACES: sRGB
Octane Render settings: buffer: HDR (Float 32-bit) Colour space: ACEScg

Octane light set to texture mode with float texture at 1.0 and light level which exposes the mid grey correctly.

Colour science: ACEScc
Version: Aces 1.2
input: CSC - ACEScg
ACES output: sRGB
Process: ACEScc AP1 timeline space

Hi Chris,

thanks for your detailed explanation.

For a first test I would suggest to check the render pipeline in the most basic way.
Use the texture without any light or shading and check the values then.

I recreated your red, blueish and grey texture in Affinity Photo with the values you noted down and loaded a JPG of that texture into Nuke with the IDT (sRGB-Texture).
Here are three sceenshots of the three color values of your texture converted to ACEScg. The viewer is the same as yours, Output sRGB.

If you render your texture without any shading or light in the scene, you should be able to sample the same ACEScg values in your render viewer.

In your screenshot the red texture shows values of 0.914, 0.157, 0.122. There seems to be something off.

I hope this helps.



Hi Daniel,

Thanks for taking time to look into this. I looked at your images but still e.g. 255, 40, 40 is not being rendered as that but more like 205, 13, 24. If my clients brand colour is 255, 40, 40 I need to send back files with the exact same colours in the renders i produce. This is a simple example but if its a client product with lots of graphics and colours its very difficult to colour correct in DaVinci. Is there something I am not understanding?

I removed my Octane Lights and left on default evironment lighting at white but I am getting the same results.

Your values 0.19827, 0.22008, 0.88834 Are they linear values, I still havent quiet got my head around working in that way)

Thanks, Chris

Hi tried something else.

I used:

for my config input and the colours are coming out almost spot on. I will have to test some more.


Hi Chris,

I am afraid you are looking in the wrong direction.

Your texture has sRGB values, they only have a meaning on a sRGB display. The moment you use any other display rendering transform apart from the standard sRGB, these values don’t have the same meaning anymore.

Search for sRGB Texture in the forum, you will find many threads about this topic.
I did an attempt too to understand the "problem. You can find my post here.