My good friend Dean convinced me to keep going on this piece. It's got great elements to practice in Painter - the beard, books, colored glass, etc. I just finished detailing the old man's face and shirt, and about to start on the beard. I'm enjoying all the different light sources - the yellow from the window, the blue reflective light from the jar, and some soft warm light source in front/left of the figures that you can't see. Maybe candles or lanterns. Got to keep in mind that there's also reflective light coming off the table.
Note to self on painting beard - remember that there is a face underneath it, and that it's not just a nest of brush strokes. It has peaks and valleys, just like hair on top of the head, just more bristly. Ignore the urge to start painting the strands and highlights, get the shapes first. Think about how it would look if the beard was sculpted.
Something was bugging me about the boy. Flipping the artwork helps me see my problem areas. In this case, the crown of his head wasn't high enough. I really should flip artwork earlier in the process.
Dean also suggested I post my progress, so I will try.