this guy is simply talented. the stroke are very messy yet u can see the form very well.the light is shining from the top and the area is a little spoky. I can confirm at he started in gray scale. This time i chosen a easier one, hope will learn some great skill.
okay. found new clues again. when i zoom in. the brush is really soild. start with a base and start to fill in the brightest light. He is definitely using some flat brush. with opacity control. I zoom in and did a small area and i manage to get quite close.