Thanks guys.
@Bob: to define the details, I use very thin washes of oil paint. I never use black, but usually stick to dark brown or grey.
In this case, I've used Van Dyck Brown.
I apply the washes with a very fine brush. Then I let it dry for about 30 minutes. The paint will feather out and the lines will look a bit messy. To clean the lines up, I use, again, a fine and clean brush and dip it in clean white spirit. The tip of the brush needs to be damp, not wet! Gradually, I then start to clean up the lines until I achieve the desired effect.
I also use very translucent filters of oils and enamels to create slight color differences. Very easy to do and with great effect.
Grtz
Flip
