undercoat of paint for weathering

Though I don't use this procedure myself, I have seen it done on a few models. They will spray the entire model in a black base coat. Then apply light sprays of whichever base coat they are using for camo. Just be careful, don't put the camo colours on too thick or you will totally loose the effect.

There are a few ways to darken the panel and recesses of a tank. One being either priming the tank in a dark shade or airbrushing the areas in black then blending them into the basecoat. I rarely do this. I use Winsor Newton Oil paint to do all my weathering and accenting of panel lines (I use Tamiya Acrylics almost exclusively for my base coat). Heavily thinned oil paint will do the trick in my book.

how do u blend?

The best way to blend the basecoat into a shaded panel line would be to not heavily spray into those areas. When spraying the basecoat, give almost a clouding on the outside panels, this should blend into these recesses. After weathering this should give you a nice blended effect.

GRACIAS

There are some demo videos/pictures of the pre-shading (undercoating with a dark color) technique by Brett Green at www.scaleworkshop.com. Might give you a few ideas.

Cjohn