Lets see if I can put it in words (Minnflier and his neat pictures are not around, darn). Scallops are where you start at the leading edge of the wing with a solid colour. And paint back the wing say 1/4 to 1/3 of the way solid, in one colour. At the end of the band of paint instead of finishing in a straight line you end the back of the painted section with the end cut with circular cut outs. Imagine a series of perfectly symmetrical waves. The base of the wave is the leading edge. The tips of the waves point at the trailing edge. The series of waves go spanwise on the wing. I don't think I can make it any simpler with words ( I am getting tired and my brain won't work). Once you see it you will see how really simple it is.

WW1 Fokker D-7's and several others had scalloped trailing edges. You want to create that effect on the front half of the wing with paint. Good luck with your project.

Mark Shuman