I have some questions about the way Vray applies color corrections in VFB. There’s something strange happening with the Curves adjustments especially. If I use curve adjustments on their own everything is fine but if I also enable the Exposure tab and start adjusting settings there (exposure or highlight burn), the dynamic range seem to diminish and the image becomes washed out especially in areas of higher light intensity.
I made an experiment by saving the image as EXR, loading it in After Effects and changing the exposure and curves the same way as in VFB and I found the results look different. There was also no washing out of colors in areas of high dynamic range/ high light intensity. Where does the difference come from? I specifically made sure that I added the Exposure and Curve adjustments in After Effects in the exact same order as in Vray’s VFB - first is Exposure and then Curves. The results were different than VFB. Funny enough, if I put Curves before Exposure in After Effects, I get almost the same washed out image as in VFB.
So does that mean that in VFB Vray first applies Curves adjustments and after that exposure adjustments instead the other way around? It seems to be the case from what I see in After Effects. Wouldn’t then be more logical for their places to be switched in VFB if that’s indeed the case? In this regard, are there future plans for VFB to manually pick the order in which color corrections are applied similar to After Effects and Photo Shop? Sorry if my question is stupid.
V-Ray does indeed apply curves first and then exposure. The order in V-Ray 3.50 beta 1 specifically is:
White balance
Levels
Curves
Exposure
Hue/saturation
Color balance
(For display only) sRGB/LUT/ICC/OCIO
Choosing the order manually is something that we have discussed, but it will require us to expand the UI a bit. I guess it’s something that we should do sooner or later, as for some cases the default order might not be convenient.
Wohoo! It works! :o Thanks for this small but very important fix.
Below are some screenshots to show the difference. Now, if only it would be fixed when using OCIO too. (notice the dynamic range clamping in the OCIO+curves example).
Now, if only it would be fixed when using OCIO too.Nope, we won’t be doing that. OCIO *must* be the last color transformation applied. It is strictly a *viewing* transformation. It is supposed to include whatever curves you want baked in it, along with sRGB conversion as needed.
If you do want to use OCIO after all, then your curves should not clamp the colors (make sure the right point is not completely horizontal, but has some upward slope). In any case, I’m not sure why you’d want to use OCIO and the curves in such a combination. With the curves, you can get the same transformation as the OCIO profile anyways.
(notice the dynamic range clamping in the OCIO+curves example).
