I  sprayed a matte retouching fixative on my charcoal drawing yesterday to hold the charcoal on the canvas.  Then I painted over it a touch of a light transparent wash mixed with Van Dyke Brown oil paint diluted with Gamsol.  The idea is to create a tea stain over the sprayed charcoal to hold my drawing in place.  Otherwise, the charcoal will easily smear and create a muddy mess.  
 
Today I added a layer of blue oils mixed with a hint of cobalt violet to the canvas.  The object is to begin a background for the sky on the underpainting. If this dries well tomorrow,  my next step will be to begin adding the grisaille.  
 
 
I’m always a bit afraid to start the grisaille on my paintings because I feel very strongly that I must be totally committed to the underdrawing before I move forward.  I believe that the design and drawing stages are easily the most important steps in any oil painting. The drawing acts as a scaffold-like structure. With a good drawing in place, the artist can be free to express light, shadow, character  and mood. A drawing can therefore make or break your painting.