Learn the technique of airbrushing for color and how to use an airbrush for softer tones in this free how to video on making a surfboard.
Although you can airbrush a board, I do not really like airbrushing that much, because it is not permanent and I try and make all my boards to last as long as I can. If you airbrush a board red, it will be pink in a year. Now artwork like this, this is sprayed on. See the front here; Hawaiian family wanted me to do this on their board "He Hawaii Au", love our state. The problem with airbrush is the board tends to be weaker, due to the fact that the color sticks to fiberglass and the resin does not stick to the foam because it can not get there.