I've been wanting to practice working up texture and color variation in digital art without relying quite so heavily on filters, so reused the G1 Elita sketch to try out a different coloring process. It's subtractive, done by putting on bright, completely opaque colors and then pulling them back out bit by bit with a low opacity eraser. Only used three different types of brushes and could have done it with two.
A more complicated or refined picture would be pretty time consuming, but I love the way the colors interact.