The One-Quarter Size Sketch
When I was doing portraits, my routine procedure was to present two rough color sketches to the client. These were done 1/4 size so it was easy to work on them as well as to enlarge them. It was also easy to visualize what the final painting would look like.
I learned that this was a logical way to work...easy to make changes and solve design problems without investing too much time. I do this often when I am doing a large painting. In this case, I am doing a drawing in burnt sienna and burnt umber on a piece of illustration board cut to 12 x 15, dimensions 1/2 the final size, but the area is 1/4. Which is why it is called a quarter-size sketch. The final painting will be 24 x 30. All I have to do is double the dimensions to my final canvas.
Here is the preliminary drawing/sketch. Basically this is the drawing as an underpainting. My next step will be to go over this in color.