CFLs emit light from a mix of phosphors, each emitting one band of color with some bands still in the ultraviolet range as can be seen on the light spectrum. Modern phosphor designs balance the emitted light color, energy efficiency, and cost. Every extra phosphor added to the coating mix improves color rendering but decreases efficiency and increases cost. Good quality consumer CFLs use three or four phosphors to achieve a "white" light with a color rendering index (CRI) of about 80, where the maximum 100 represents the appearance of colors under daylight or other sources of black-body radiation such as an incandescent light bulb (depending on the correlated color temperature).