The words that the English language uses to define human skin tones are imprecise, and doesn't capture the wide range of colors that exist in the human palette. Angélica Dass attempts to catalog human skin tones by identifying individuals with the Pantone Goe System.
Brazilian artist Angélica Dass (Pantone 7522 C) undertook her Humanae project as a means of discussing cultural and racial identifiers. Each subject is photographed against a backdrop that is the same color as an 11x11 pixel space on their face. The result isn't a complete depiction of each subject's skin color and isn't nearly the "scientific measurement" Dass claims it is, but when the images are seen together, it's interesting to see the shifts and changes in skin color, even between people who may well share similar ethnic backgrounds.