Here is my technique for coloring. I've shown most of the steps here. First I draw something on Bristol Board. Then I ink it if I don't mind attacking the original art. After that I scan it and touch up the lineart in Photoshop. Next I either make a new layer with the lineart set as a screen or save it as a channel. Then I create what is most commonly called the "Flats". This is for color separation and makes it so if I have color correction later I can just grab the desired areas without having to do a lot of precision wanding in Photoshop. I duplicate the Flats and begin to color. I then add the inks back in adding any effects I choose. After that I added the background star field, and the halo around the character and glow of the power ring and emblem. Then I wondered what Superman's colors would look like and tweaked the desires colors. Ta Da!