It's a Citadel Bleached Bone basecoat with an old GW Flesh Wash and a very very light Citadel Devlann Mudd wash on the tail. To produce the highlights, I ran the tip of my finger along the high points of the model such as the crest of the skull before the ink had fully dried.
I have to say my own preferred paint scheme is Citadel Bleached Bone with Devlann Mudd Wash accenting, for a 'Pitch Black' Demon effect as described in one of my previous posts. It's just more 'menacing' and 'other worldly' IMO.
For me, these Hammerheads are the real star of Khurasan's Space Demon range....and I want more!!!!!
Cheers
Mark