[Bf-codereview] Gamma Node for Cycles (issue 5488046)

[dfelinto at gmail.com]

The gamma node is doing a simple pow operation:
color_out = color_in ** gamma (as in 8 = 2 ** 3)

And looking at your sample file it seems consistent.
Linear ** 2.2 = sRGB
sRGB ** (1/2.2) = Linear

You don't use gamma 2.2 to linearize a sRGB image to Linear. You use
1/2.2 for that.
Gamma 2.2 is the gamma already present in the sRGB colour space.

http://codereview.appspot.com/5488046/