Human skin darkest brown to the lightest pinkish-white hues. Human skin shows higher variation in color than any other single mammalian species and is the result of natural selection. Skin pigmentation in humans evolved to primarily regulate the amount of ultraviolet radiation (UVR) penetrating the skin, controlling its biochemical effects. The actual skin color of different humans is affected by many substances, although the single most important substance determining human skin color is the pigment melanin. Melanin is produced within the skin in cells called melanocytes and it is the main determinant of the skin color of darker-skinned humans. The skin color
Diarylide pigment with the same coupling partners. The molecular structures of these molecules is more conjugated than represented in the images shown below. The pigments' colors can range from yellow to green. One of the most common diarylide yellow pigments is Pigment Yellow 12. Its CAS number is . Other diarylide yellow pigments include ‘’’yellow 13’’’ , ‘’’yellow 17’’’ and ‘’’yellow 83’’’ . These pigments share the same backbone and vary in color depending on substitution of the benzene rings. Worldwide production of color organic pigments was estimated to be about 250,000 metric tons (t) in 2006, with about 25%, or 62,500