CGTalk - Gain and offset & gamma issue

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kreuz

11-17-2008, 01:09 PM

Hi guys,
there are something bother me in my color correction cases.
I have already check the help documents and search the ideas of gain and gamma in internet, and i only know about they both are related to lightness and darkness. The documents shows that the gain parameters is something like the exposure values of photography, but i am not really sure that both of them are quite different from the contrast or the level or curve functions.Like when i use color correction adjustment in CB , i use curve to moderate the brightness and darkness and sometimes combined with saturation and contrast, but i was really fascinated in gamma or gain the kind of functions and i would like to know what do they do in color correction and what's the tricky way or necessary skills that i have to know in composition.
Could anyone spend some times to explain these for me?
BR,

Kreuz

Kai01W

11-17-2008, 08:06 PM

Well it is rather easy: gain works like multiply. Raise it and brighter tones become brighter faster than darker ones. black remains black (x*0=0). Offset works like add (or subtract) everything becomers equally brighter/darker. This also affects your blacks. Thats why it is used not so much for normal color correction but rather for more technical corrections (a generalisation, I know).
Gamma. Keeps your blacks and whites and will adjust your midtones...

Create a black to white gradient in the paint module and play around with the three functions. You'll get it quite quickly.

-k

kreuz

11-21-2008, 10:10 AM

thanks a lot, it really helps.:p

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