Amazing friend, quite realistic. I am aware that the portraits are very complicated to do, be it black and white or color. It should delineate very subtly and focus on each element of the face.
I loved how you used the game of shadows especially on the chin up to the neck, and the details of the hair also shows a good job. I think it's great that you explain the procedure in order to learn one thing or another.
Thank you friend. I guessing you’re an artist as well.