I'm in the middle of coloring page 80 of the comic, and I thought people might get a kick out of this. I do a 5-color process when coloring most characters' skin -- 3 shades (light, medium, dark) of their skin tone, followed by, on average, 2 shades of my 'shadow grey' color (which is a blue/grey/purple color, rather than a true grey.)
This is what the before and after of using the shadow grey looks like!