The Shades Color Picker adds an additional pane to the standard Apple Color Picker. It is designed to help you choose colors by showing you grids of related colors. Shades uses Hue - Saturation - Brightness (HSB) color coordinates which many people find more intuitive than Red - Green - Blue (RGB) color coordinates. To use Shades, you choose a center color, a step size and a color coordinate (one of H, S or B) to hold constant.