Hi Rob and Russ,
You have the basic idea regarding the use of the 3 toned fading technique. I generally pre-moisten the surface with a little turpentine (just a little) and then add a few dops of the paint onto the surface. And then simply work the oil into the surface using a larger sized (flat) soft brush. The process can be repeated once this application has dried.
Also, I like to add a few drops of other colors into the mix - such as a little Olive green onto the green fields and maybe a little Wash Brown or Brick Red onto the brown fields.
Please don't hesitate to contact me directly if you have any questions:
[email protected]Have fun,
Rick