| Drawing on with HB pencil is good for a bit of chipping and rubbed areas, use it very sparingly though.
If you do a wash or pastels, again be very sparing and use very thin paint; less is often more in weathering land.
Another handy thing is a very fine black pen (those fineline things, nothing special) can be used to accentuate some areas that would benefit from darker sharp lines (obvious weld seams, hatch & plate joins etc.). |