Dark Letters on a Light Background
With the monitor off, look at your reflection in the screen. Now turn the monitor on and select a Windows type background, (black letters on a white background). Notice how you cannot see your reflection as well.
Contrast is simply the difference in the brightness between two images. With a white back-ground, we reduce the difference in contrast between the screen and what is reflected off of it.
Negative screen contrast (black letters/white background) can reduce reflected images, as we saw with the demonstration. A white background also reduces the luminance (brightness) difference between the screen and the surrounding background of a normally lighted office. Snyder, et al, (1990) found performance increases, and Bauer and Cavonius (1980) found a lower error rate with dark letters on a white background.