I'm asking this on behalf of my brother, who has been having a long running debate with the other Ultramarine player in our group about how to pain them.
My brother primes with skull white then basecoats in ultramarines blue. It gives a a nice, glowy effect in my opinion.
His nemesis primes with chaos black, then drybrushes successive layers of ultramarines blue onto the model. It seems to give it a much darker, grittier colour though I'm not sure if thats the chaos black or the drybrushing coat.
My brother things the other chaps Ultramarines are too dark, the other chap thinks my brothers are too light. How do you do yours?