When Red + Blue + Green = White When light waves of different wavelengths are combined, the wavelengths are added together, producing the perception of a different color. Thus, when green light is combined with red light, yellow light is produced. When the wavelengths of red, green, and blue light are added together, we perceive the blended light as white. If you’re wondering why mixing paints together produces a muddy mess rather than pure white, it’s because the wavelengths are subtracted rather than added. Each color of pigment absorbs a different part of the color spectrum, and each time a color is added, less light is reflected. Thus, the mixed color appears darker. If you mix all three primary colors together, they absorb the entire spectrum—so we perceive the splotch as black.