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Representation of the three groups of lip color highlighted by HAC (hierarchical ascending classification) based on the L*, a*, b*, C*, and h data on bare lips (superior and inferior) (SpectraFace® images). Group 1: darker and redder inferior lip. Group 2: lighter and yellower inferior lip and yellower superior lip. Group 3: inferior lip tone as light as the second group and as red as the first group with a redder superior lip.
