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gamma correction


darth
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well, throb's site is really cool and all, but i still don't understand what "gamma" really is to tell the truth :p

 

how do i know that my monitor is not linear or maybe it is? you already have to be a scientist more or less to understand the basics!

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From Wikipedia:

 

Gamma correction in photography, television and computer display systems. Gamma is the exponent in a power-law relationship between video or pixel values and the displayed brightness. In photography it is the slope of the curve of (density or log(opacity)) of the film image versus log(exposure) (the Hurter-Driffield curve), in the straight line region.

 

Um, for non-scientists (and I'm not an expert so somebody else can feel free to correct me if I screw up):

 

You have a white point and a black point in your color space, everything else happens in between. One of the things the color profile does is to assign the brightness of these in-between values. Monitors and Photoshop are using one color profile, and Max and Vray are using a different one, so the brightnesses come out differently. Fixing this causes extra work, so it's useful to just have Max and Vray use the same values.

 

The curve that you can enter in VRayFrameBuffer represents the difference between the normal (sRGB) color profile and the Max/VRay profile, so when it's added to the VRay-profiled image the result is an sRGB image, which will display correctly and read correctly in Adobe programs.

 

The link has a graphic that shows the effect of adding the curves.

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