color balance A monitor uses three electron guns (one each for red, green, and blue) to excite the phosphors that make up the pixels in an image. Color balance refers to the relative strength of the signal from each of the three guns. If the blue gun is turned up higher than the other two, for example, you will see a bluish tint on the screen. Many monitors provide color adjustment controls, which allow you to adjust the relative strength of the three electron guns to correct the problem. See also: color purity, electron gun, pixel, refresh rate