Have a look at these outstanding ink and watercolor Skull paintings by Chris Panatier! A lot of people color their hand-drawn pieces in Photoshop but Chris uses watercolors for all the color and titanium-white gouache for the bright whites. A few years ago he begun doing ink and watercolor illustrations for various musical outfits, mostly metal bands.
I absolutely love the careful attention to details!
Be sure to visit him online to see more of his amazing art. There is more to discover, his work is very varied. You can follow Chris on his website, Facebook and deviantArt.