Margaret,
I think you hit the nail on the head. Because it has been some time since I delved into the creative process, and my last pastel was just to see if I could still use them, this one has a little more thought behind it. I wanted a rich purple background, highlighted as shown in the painting, and couldn't see the wood for the trees. When I had a look at the painting this afternoon, after reading your comment, it seemed so obvious. Lesson 384 is; be more objective.
(Also, lesson 1, listen to my wife. She said it "cheapened" the portrait, which was the opposite of what I wanted to achieve. Now if she had said it was