Thus the more white, the less saturated. A color with a high value would have little or no black, whereas colors with a low value would contain more black. Irrespective of Hue and Saturation, a value of zero produces a pure black. Sorry Gary, I can't help - but I can tell you about a different way I have displayed the curl visually. My method was to use MM Toolbook to display a small rotating paddle wheel.
Students can click on a map of the Atlantic Ocean and see the paddle wheel rotate faster or slower.