I started with a scanned pencil drawing. Using the Pen on a new layer I sketched over the old pencil sketch. Next, on a new layer in between the first two I used a transparent airbrush to block in the color. Then on the same layer I used the oliy artist brush to get more marks and mix the colors a little. After that I used a charcoal on the top pen layer to make the marks a little stronger. Since I am better at drawing than painting, the work looks better when my drawing shows through.