Color Field Portrait?

I had an interesting discussion with a local artist on Glenn Brown's work, particularly his use of flat color background. She thought that supports the subject of the painting (see the first figure. I thought his more successful ones using this approach is when the "background" occupies less area on the canvas. To prove to myself that this is the case, I painted the portrait of Madam X shown here in the second figure. I intend to make the "background" competes successfully with the figure itself. Yellow is usually a difficult color to deal with - its intensity depends very much on the neighboring colors. I chose it as "background" on purpose, and see whether I can make it very intense. You may need to click on the figure to enlarge it in order to see the intensity of the yellow.