(Warmaster Nice @ Apr. 02 2008,16:35)
QUOTE
My own BL as shown in the Online store was painted using an undercoat of Chaos Black. Then add consecutive layers of chaos black, first mixed with regal blue and then adding some white to the mix. If the result get too blue/grayish you could wash it with thinned down chaos black again.
An alternative method might be to use black basecoat, then a heavy drybrush of Shadow Grey followed by a wash of chaos black again (Water/paint ratio depending on how black you want it to be again.
The final solution is to use a white undercoat and use a black ink. Add a bit of black paint to the ink to make it look less shiny and wash it all over the model. It's a bit trikier, but if the white spray undercpoat has been evenly applied it should look alright. It will however require varnish afterwards to stop the ink from wearing off over time.
I'd say that is a pretty definative answer
.