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 yellow along with magenta and cyan. Canary yellow is derived from the colour of an average canary bird, though canaries can vary in colour from dark yellow to light pink. Process yellow is not an RGB color, and in the CMYK color model there is no fixed conversion from CMYK primaries to RGB. Different formulations are used for printer's ink, so there can be variations in the printed color that is pure yellow ink. The first recorded use of "canary yellow" as a color name in English was in 1789. The color defined as yellow in the NCS or Natural Color