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
Color scheme such colors as red, yellow, and orange arranged together on a black background in a magazine article. The addition of light blue creates an "Accented Analogous" color scheme. Color schemes can contain different "Monochromatic" shades of a single color; for example, a color scheme that mixes different shades of green, ranging from very light (white), to very neutral (gray), to very dark (black). Use of the phrase color scheme may also and commonly does refer to choice and use of colors used outside typical aesthetic media and context, although may still be used for purely aesthetic effect as well as