Human hair color account for all possible shades of brown, blond, or red (for example, platinum blond versus dark blond/light brown), nor does it explain why hair color sometimes darkens as a person ages. Several gene pairs control the light versus dark hair color in a cumulative effect. A person's genotype for a multifactorial trait can interact with the environment to produce varying phenotypes (see quantitative trait locus). Natural hair color can be brown, blond, black, red, or white; all natural hair colors including grey, white and lightest blond, are shades of brown. The Fischer–Saller scale, named after Eugen Fischer and , is
Shades of white "Navajo white" is a whitish orange color, and derives its name from its similarity to the background color of the Navajo Nation ethnic flag. In 1987, "Navajo white" was included as one of the X11 colors. Displayed at right is the color alabaster. There is no evidence that this color name was in use before the X11 color names were formulated in 1971. Shades of white Shades of white are colors that differ only slightly from pure white. Variations of white include what are commonly termed off-white colors, which may be considered part of a neutral color scheme. In color