In this gorgeous portrait John Singer Sargent makes very few value changes in the light areas of the face, he instead used color to indicate subtle anatomical changes. I made the image black and white so you can more clearly see how he grouped his values. Look for example at the jawline, there is almost no value change, he was able to turn the form by changing the color to a greenish grey. He does this all over the light side of the head. (Click image to enlarge)
