Illustrator, concept artist and comics artist Robert Chang works in both traditional and digital media. His 2D digital work is often done in Corel Painter and Adobe Photoshop. The “Goodies” section of his site includes tips, techniques and downloadable custom brushes for Painter. There are also several excellent and detailed tutorials for his digital work, including the image shown here.
Chang is the co-author of a book on digital painting techniques: d’artiste (Ballistic Publishing).