Shades of white are colors that differ slightly from the CIE standard illuminant D65, a white point that represents the average color of daylight at noon. There isn't one objectively pure white, as noon daylight varies by location and atmospheric conditions, and the choice of using D65 instead of direct sunlight or a white point on the Planckian locus is arbitrary. For simplicity, this article will use the term pure white for the D65 white point.