Most displays viewed in dark environments can easily cause daz-zling glare and affect a viewer's dark adaptation state (night vi-sion). In previous work we showed that legibility could be im-proved and dark adaptation preserved in low-light environments by using a display design with a specially selected spectral light emission. We used long-wavelength light (red) that is easily visi-ble to daylight vision photoreceptors (cones) but almost invisible to night vision photoreceptors (rods). In this paper we conduct an experiment in which we show that negative polarity (bright text on a dark background) produces better performance in a legibil-ity task than does positive polarity (dark text on a bright back-ground). Our results can serve as a guidelines for designing dis-plays that change their color scheme at low ambient light levels.