I changed the floor color in glossy-lighting.inc and saved it under a different file name. I changed the RGB values to 0, 0, 0. The floor and sky turned black. Now, when I change them back, the area the spotlight shines on (I didn't change the spotlight at all) is affected, so I can make a little red circle, or a green circle, etc. However, I cannot change the sky and rest of the floor. I'm not sure what's going on, but I did tinker with the spotlight's color after that, and I got a nice color balance, but there's so much black it defeats the purpose of the colors I used.

Is there any chance someone could actually write an INC editing tutorial?