So, now that I've finished the grisaille, I can start using color. I experimented with it a little last night, but only on a couple of places that I was certain were completely dry.
I ran off to the art supply store yesterday in search of Holbein transparent oils, as I think they'll work really well on top of the grisaille. The background wall color is an interesting and rich combination of red, yellow, and green. The chalk work on the blackboard is mainly blue. It's going to be so much fun to work on.
The Happy Hour, work in progress, (click on image for larger view)