Just look at the above art by Michelangelo. It is so good that I get clean bowled. The dark and the light areas are so well drawn. The drawing seem to pop out in 3d.
I want my drawings of portraits this way.
I am going to follow the following principle to be able to draw like Michelangelo. " if there is cosine hatching for dark, then there is cosine hatching for light"
I intend to use above principle and experiment and try to get a superb finish.