Step 3: Separate the Dark/Light Tones

Now we will create 2 more layers in between the line art and the color flats. One for dark tones and another for lighter tones. These three layers will supply different value ranges to make our shapes volumetric with our flat color being the midtones. I like to make palette swatches for my 3 colors per blocked out color to use for the initial shading to make it more convenient to access my colors.

Use the Magic Wand Tool to select the blocked out flat color then airbrush on the edges and work your way into the shape. Be sure to paint in the appropriate layer. I like to pull out the forms with the darker color by tracing along the lines until volume begins to fill in and around the lines

When painting into the lighter value layer I like to do the opposite of what I did in the dark value layer. Instead of painting from the edges in, here we will be painting from the center out creating even more volume. After this you should be able to hide the line art and see distinctive shapes.