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 brown a wide variety of colors, including shades of yellow or red. Browns are usually described as light or dark, reddish, yellowish, or gray-brown. There are no standardized names for shades of brown; the same shade may have different names on different color lists, and sometimes the one name (such as beige or puce) can refer to several very different colors. The X11 color list of web colors lists seventeen different shades of brown, but the complete list of browns is much longer. Brown colors are dark or muted shades of reds, oranges, and yellows which are created on computer and