Sorry for the late reply. Its is definitely the tone-mapping doing its job on the highlights here. If I may, displaying a linear image/render with an sRGB function is incorrect. My favorite quote from Thomas :
“Friends don’t let friends view scene-linear without an S-shaped viewing transform”.
I totally understand what you mean by loss of details and contrast but you should not compare to the left image because it is basically incorrect. I’ll quote Doug Walker here :
The way that the Linear Workflow is often described contains a crucial error. Usually the description implies that the viewing process simply inverts the gamma adjustment applied on the input side. However, this is wrong and will lead to results that are too low in contrast, have too light a mid-gray, and have clipped highlights, therefore requiring artists to compensate by biasing the lighting and material decisions in unnatural ways. In order to correct this, the viewing transform must account for the fact that the input is what color scientists call “scene-referred” whereas the image being viewed on the monitor is “display-referred”. This means that the viewing transform should not be a simple inverse gamma and instead needs to incorporate what is sometimes called a tone-mapping step.
So I don’t know what stage is your project. But you may have a few options here :
- Go back to look development, check your albedo/spec values, your light’s exposure (if you have time) with the ACES ODT activated
- Try to compensate in Nuke (not ideal at all) but it would be faster in the short run.
To sum it up, we are comparing two images : one with no tone-mapping (with clipped values that seem to give contrast) and one with tone-mapping (which looks flat but is in fact technically correct). To give you an idea, to reach a display-referred value of 1 with ACES, you would need a scene-referred value of around 16. You need to put a lot of energy in your scene to reach these values. When a project has been developed under certain display conditions (sRGB for example), it is difficult to just apply an ACES ODT (which is quite heavy on the look) in its last stage. If you send me an exr, I am happy to have a look.
Hope it helps,
Chris