Created and applied LUT in VFB looks different

[Oleg_Budeanu]

Hello
So I have an animation project going on and I've done some color corrections in VFB.
Now, I want these color corrections to be transferred to photoshop/after effects.
First, I exported CCs as a LUT file.
After that I tried to apply the Lookup Table CC in VFB with that LUT I created, just to check if they are the same... and they are not.
The same is in PS (I apply it to 32 bit float EXR)
What's the issue? Isn't that supposed to be exactly the same?
This is Filmic Tonemap : https://dl.dropboxusercontent.com/s/...CwVAobqMsk.png
This is LUT created from that Filmic CC : https://dl.dropboxusercontent.com/s/...stpYvKpIs6.png
You can see that they are very different in highlights. And that's a comparison straight from VFB. I did not change anything else.
Exactly the same result is in Photoshop 2023, looks exactly the same.
How I can crate that LUT to be exactly the same as the color correction of Filmic Tonemap?
Thanks

[piotrus3333]

You need a .csp lut to be able to tonemap with lut in PS. No other lut format has access to hdr data in PS.
Example attached.

[piotrus3333]

Filmic AMPAS for PS here:
Tonemapping with LUT in Photoshop / Affinity Photo - Chaos Forums

[Oleg_Budeanu]

Hello Marcin,
Thanks for the information.
But I am applying that in the VFB. Exporting LUT from VFB and importing to VFB. And it's different.
In the PS I am applying LUT with the same (different) result from Filmic Tonemapping.

[piotrus3333]

VFB can export luts only for 0-1 colour range. It also can not process correctly any luts for colours above 1. Use Reinhard/CineonLog in VFB an do your corrections on top of that - then you can recreate this process in PS 1:1.

[Joelaff]

I can load LUTs made with the vfb in fusion that are applied to linear images with brightness values in the range of 0.0 to over 900.0 and they work fine, but I have never tried a LUT in PS.

Is this just a PS thing?

[piotrus3333]

I can load LUTs made with the vfb in fusion that are applied to linear images with brightness values in the range of 0.0 to over 900.0 and they work fine, but I have never tried a LUT in PS.

Is this just a PS thing?

Sure, you can load them and input for the range covered by lut from VFB should be correct (0-1 max). But what happens above 1 is simple interpolation of last two points of the lut. The interpolation part is software dependant, works in Fusion but might not work somewhere else.

edit:

[Joelaff]

I see; interesting, and unfortunate. That explains why I often have to do further highlight compression.

[Oleg_Budeanu]

Thanks. So VFB exports correct LUT which works in 32 bit mode, it's just that some applications are not working with it correctly, right?
I tried that in After Effects and I had to waste a lot of time playing with color spaces to get close to what I see in the VFB and LUT exported...
Do you know correct workflow on how to export color correction settings from VFB to AfterEffects? Everything in 32 Float, I am exporting 32 bit Float EXR.

[piotrus3333]

No. VFB does not export luts that cover above 1 range. It also does not process correctly luts that cover hdr.

There is no one correct workflow. Do you need something standardised or just something that works?
I use ocio and luts from Resolve. Color space / tonemapping with aces ocio and acescc luts to see color grading in VFB.

Your VFB adjustments should be tonemapping + color grading. And only color grading part (within ldr 0-1) can be exported via lut from VFB. Then just use tonemapping that you can easily replicate in comp:
any parametric filmic, reinhard, any log (you have cineon log in VFB as log), whatever works for you.

[Oleg_Budeanu]

No. VFB does not export luts that cover above 1 range. It also does not process correctly luts that cover hdr.

There is no one correct workflow. Do you need something standardised or just something that works?
I use ocio and luts from Resolve. Color space / tonemapping with aces ocio and acescc luts to see color grading in VFB.

Your VFB adjustments should be tonemapping + color grading. And only color grading part (within ldr 0-1) can be exported via lut from VFB. Then just use tonemapping that you can easily replicate in comp:
any parametric filmic, reinhard, any log (you have cineon log in VFB as log), whatever works for you.

Hmm, but Joelaff says that
"I can load LUTs made with the vfb in fusion that are applied to linear images with brightness values in the range of 0.0 to over 900.0 and they work fine"
Or I misunderstood something?
I search for an easy way to transfer the corrections from VFB to AfterEffects. We did a series of stills which were processed in VFB and now we are creating animation for the same space, so I am searching for a way to make them to look exactly the same. Basically it's just about copying Filmic Tonemapping to AE. Maybe there are a series of color corrections which I should apply in AE with the same settings taken from Filmic Tonemapping?

[piotrus3333]

presentation by John Hable, original formula somewhere in there:
Hable John Uncharted2 Hdr Lighting (slideshare.net)

Filmic Tonemapping Operators – Filmic Worlds :

something like: ...((x*(A*x+C*B)+D*E)/(x*(A*x+B)+D*F))-E/F.......

[piotrus3333]

or something simpler: UE3 filmic or my modified version:
https://youtu.be/1hcTxH43pMU

[Oleg_Budeanu]

Thanks, Marcin, very useful information!

[Joelaff]

I misspoke. In fusion the LUTs do not precisely match the VFB.

I am not sure precisely what is going on. I can indeed apply a LUT to a shot with 0-900.0 and get results in fusion, but those results are not precisely the same.

Normally, we just start tone mapping from scratch in fusion. But on some recent projects made use of the LUTs out of the VFB.

If I am understanding piotrus3333 correctly it sounds like the only effect the VFB LUTs can have outside 0-1 would be gain based on the slope of the line between the last two points of the LUT (per channel?). So since we significantly rolled off the highlights we still got significant gain reduction in that 900.0 value, but linearly rather than a nice roll off.