oh!  and also a note:  even though i'm saying GC, it's really sRGB correction.  GC is an approximation, and the sRGB equations are slightly different though much more complex node-wise.  GC gets really off towards the lower end of light, with sRGB being both darker and more saturated. you ever read people saying they don't use GC because it makes stuff look grey and washed out?  well, it actually does do that.  sRGB doesn't.  not a big difference in even strong light of bright colors, but (imho) highly noticeable in any situation that has low light, which includes surface shadowing, cast shadows and diffuse colors.    but people know GC now, so that's what i'm using as a label.