Portrait Painting Impress is a name of a YouTube playlist, collection of videos made for Zin Lim's oil painting classes and workshops. The classes and workshops cover how light reveal forms and shadow edges, how light create beautiful value pattern and how it works for human eye. If you are interested in studying this direction of approach for figure/head drawing, see upcoming classes near you.
On Demand Video Tutorial
Full description of painting process includes reference picture with mark-ups, material list, animation on whiteboard, what artist think, see and do by stages.