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Gamma/LWF versus Kelvins...


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When using LWF with vray, i encountered a problem with IES files which work with Kelvins.


The gamma settings are affecting all the color sliders, including the one that is kelvin dependent.


I believe that the results i see in my renderings when using kelvin colors and LWF are wrong, but no one seems to notice or understand that.



This is an image where the room is being lit by a single IES (new vrayIES) light with a color of 8000K.


It is blue.






In this image, the gamma of 2.2 has been applied.





As you notice, it's not so blue any more, giving the impression of a warmer light. this is along the lines of D65 or so.



With GI, it looks like this:




But if i manually correct the color so its back to 8000k, it looks correct.







I would like to hear an opinion on this. Most people thing it's not a problem at all, but i fail to understand the concept. If the gamma setting washes out all our textures and colors and we have to bring them back by applying the inverse gamma, why shouldn't we do it with kelvins as well?

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On the contrary - I'd say that the Kelvin values you see when not using Gamma are the wrong ones. 8000K is nowhere near that deep blue. IMHO, The lighter one is the correct one.


(Disclaimer; at least this applies to the mental ray implementation)



Edited by MasterZap
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