Brightness and Contrast: controls how the background image, if any, will be shown. A low contrast and low brightness usually work well with light-colored text, and a low contrast and high brightness usually work well with dark text.

TIP: You can also right-click-and-drag on the sample projection display to quickly set the brightness and contrast. If you initially move the mouse vertically, the brightness will change; if you initially move the mouse horizontally, the contrast will change.