Cagalli Yura Attha
the problem is it isn't FOUNDRY white. buy FOUNDRY white.
I shall have to beg to differ here Caga. I never paint white. What I do, and I shall refer to the colours in the citadel names is this:
1) Chaos black undercoat
2) Shadow Grey all areas you want white.
3) Paint over the shadow grey in Ghostly grey.
You can vary the thickness of the paint. I prefer to thin it right down. To get an instant shadowing effect. It looks better than white, and it actually looks more white than painting white does. Heck with this technique, I've won and placed well in many local painting competitions.