18-Second Monochrome Face Warm-Up Sketch

Done as part of a practice session with poses of 18 seconds in length.

My current goal is: Improve my understanding of the forces of my facial muscles, in terms of my facial anatomy.

Here is my latest warm-up sketch from last night. As you can plainly see, according to my progress so far, I'm really and totally getting the feeling and movement and life of my facial muscles. So, what do you know of this?