An often mentioned third but not proven origin involves the bloody skins (red-skins) of Native people as "prizes," in which they would be scalped after battle and their skins bought and sold in local towns.
According to conservative writer Dinesh D'Souza, "Blumenbach's classification had a lasting influence in part because his categories neatly broke down into familiar tones and colors: white, black, yellow, red, and brown."
Johann Friedrich Blumenbach (1752-1840), one of the founders of what some call scientific racism theories, came up with the five color typology for humans: white people (the Caucasian or white race), more or less black people (the Ethiopian or black race), yellow people (the Mongolian or yellow race), cinnamon-brown or flame colored people (the American or red race) and brown people (the Malay or brown race). Blumenbach listed the "races" in a hierarchic order of physical similarities: Caucasian, followed by American, followed by Mongolian, followed by Malayan, followed by Ethiopian.
One of the earlier uses of the concept of “black” as a metaphor for race was first used at the end of the 17th century when a French doctor named François Bernier (1625-1688), an early proponent of scientific racism, divided up humanity based on facial appearance and body type.
He proposed four categories: Europeans, Far Easterners, Lapps, and Blacks. The first major scientific model was created in 18th century when Carolus Linnaeus recognized four main races: Europeanus which he labeled the white race, Asiatic, which he labeled the yellow race, Americanus, which he labeled the red race, and Africanus, which he labeled the black race. Linnaeus' protégé, anthropology founder Johann Blumenbach completed the model by adding the brown race, which he called "Malay" for Polynesians and Melanesians of Pacific Islands, and for aborigines of Australia. Rand McNally's map of races describes Amerindians as being the copper race or copper people.