of course, basicly every human being is a person of color--albino's are at one end of the scale, -- certain african nationals at the other end..

human skin color is made up of two components.. underlying fat, and melinin. just like chickens fat (and milkk/cream)can be made yellow(er) by a diet rich in beta carotines, some ethinic groups are likelier to have yellowish body fat, and others likely to have whitish. this 'colors the skin'--partly its genetics, and partly it is diet.

melinin is a body chemical that also colors the skin. albinos have none.. full saturation (the darkest possible tone) is based on the percentage of melinin-- but the way you body handles/distributes it.. is a formula-- and basicly there are something 36 associated skin tones that go along with differing percentages of melinin.. so 'theoreticly' there are about 72 basic skin tones..
reality is, blood (and relitive closeness of blood vessels to the skin surface) and other factors come into play..

(diet sometimes plays a bigger part than we think-- in the book The Hunan Hand--(a series of essays about quirking/interesting human 'illnesses',-still packed away, so i forget the author), one person who went on a fad diet that relied heavily on carrot (a source of beta carotine) and tomatoes, (which contain another chemical that in large quanities that can color the skin) ended up looking pumpkin orange (as if he had use a really cheap self tanner!) --while exceptional, it did highlight that diet does effect both skin tone, and color!-(the person was convinced to return to a normal diet, and when they did so, their skin returned to a normal color..