Adjust Exposure on Floating Point Footage [HDRI/EXR]

Hello community!

This is my first post here as I'm starting to research some workflow between Resolve and color grading for game engines/CG renders. So if there are any mistakes on how I'm formulating this issue please let me know.

We come from making our grades in Nuke and it is very common that the content we are working with has values that go above the range of 0-1 (or in Davinci's case 0-1023). So something that I do almost all the time for testing is importing an HDRI or EXR file that has values above 1 and then modify the exposure to reveal the extra detail that bright spots may hold.

After taking a look at how to make Davinci use a Linear colorspace and the viewer a REC709 color transform I'm still a little bit confused about the fact that the only answer right now for modifying the exposure is adjusting the gamma/gain/offset dials which is not necessarily the math that I'm looking for. So any guidance on how to do a proper exposure adjust (using F-stops or densities or something along those lines) will be greatly appreciated.

On another matter which I think is more important than the above would be the fact that when I import an HDRI/EXR image, I can see on the scopes that my values are being clipped at 1023 and thus killing all that extra information on bright areas.

I just want to understand a bit better how the content would need to be prepared for HDR grading then or if there's a way to have Resolve to not clip those values. Here's a quick screenshot showing what I mean, where if I lower the exposure in Nuke you can see how the values on the sun are preserved.

Resolve_ClampedValues.png (771.08 KiB) Viewed 655 times

Resolve_ClampedValues01.png (712.81 KiB) Viewed 655 times

Sorry for the long post, any guidance on this would be greatly appreciated! Thanks a lot and stay safe ;D

This is definitely not my area of expertise, but maybe this helps. (Or maybe someone will correct me.)

The only formats I'm aware of that can do what you want are RAW. To the best of my knowledge, any 'baked-in' format will be unable to recover clipped highlights.

Gain is the equivalent of exposure adjustment if your working space has linear transfer encoding. Offset is when working in log space. Resolve simply doesn’t show useful units in UI. Exposure is linear light value multiplied by 2 raised to the power of EV: value * pow(2.0, EV). You can do it with a dctl if you want exposure slider with numbers, and there is an exposure effect too I believe (can’t check right now).

Scopes clip because scopes won’t go above 1.0 equivalent.

This is definitely not my area of expertise, but maybe this helps. (Or maybe someone will correct me.)

The only formats I'm aware of that can do what you want are RAW. To the best of my knowledge, any 'baked-in' format will be unable to recover clipped highlights.

Raw is also baked, once sensor clips it is gone for good. Any format capable of storing floating point data (for linear light storage) or log data with good enough bit precision (basically any current di format) can do it.

Hey guys!

Thanks a lot for the explanation and now it's definitely clearer to me what it is what I need to achieve in order to do the correct exposure adjustment.

Also I was able to interpret values brighter than 1 with the correct import settings from fusion. Here's the link for reference if anyone ever needs it

https://blender.stackexchange.com/quest ... h-the-luts

That fixes the read in the higher than 1 values, but now I'm not being able to keep those values while displaying them in sRGB.

Resolve_ClampedValues02.png (689.23 KiB) Viewed 597 times

I'd like to keep the high range value but looking at them just as I would in Nuke.

Resolve_ClampedValues03.png (998.02 KiB) Viewed 597 times

Also I'm noticing that this values don't carry over to the Color workspace, does that means that higher range values are only kept on Fusion but then get clamped as soon as the are sent to the Color workspace?

My goal is to do live CC to a game engine content that writes high range values, so I'd like to know if its possible to keep those values or if I need to figure out a different pipeline.

Thanks a lot for all the help, cheers!