I used to make detailed, preparative studies in oils for my portrait commissions. I stopped gradually. Along the way I realized I was putting my best energy in a study. By the time I made the real painting it sometimes seemed as if I was repeating myself. Norman Rockwell writes: “Be careful not to carry the colour sketch so far that there will be no fun left in the final job. ( ) I have often made the mistake of carrying the sketch too far, wearing out my enthusiasm before I get to the final job”.
Occasionally, when I have time, I love to make a pencil sketch to assess what position of the model I like best. Drawing technique differs so widely from painting that I find myself delighted to get started in oil. That impatience provides good energy!