There are several things to think about when painting from a live model. One that I wasn't expecting while painting Zeno was at the end of his last sitting, when after standing up too quickly and stretching, he lost consciousness and fell face first off the model stand. Luckily, he came away with only a bloody nose.
Zeno, Oil, 11 x 14 inches
This second image is taken in raking light to show the relief texture of the brushwork. I didn't make an animated gif this time, but if you click on either image to zoom in with Blogger's image viewer, you should be able to get the same effect by flipping back and forth with the arrow keys on your keyboard.
I taught my first alla prima portrait painting workshop recently in Wakefield, RI at South County Art Supply. Despite losing track of time and rushing the end of the demonstration I gave, it went pretty well and was a lot of fun. I'll probably do it again sometime, so if you would be interested in taking a workshop in Rhode Island, let me know in the comments or in an email so I can gauge the interest level. Below are a few pictures of my demonstration in progress and the end result (with a few touch ups to fix what I rushed.)