Seeing Skin Tone Differently: An Experimental Comparison of Objective Measurements and Subjective Perceptions

Human skin tone is an important consideration in pulse oximetry and evaluating skin health conditions. Various tools are available to measure skin tone, including visual scales, palette based estimations, and optical sensor based devices. The objective of this experimental study is to compare common skin tone measurement methods. We used Fitzpatrick Skin Type (self- and observer-reported), Pantone SkinTone Guide, Delfin SkinColorCatch, and Nix Spectro 2 devices to measure the forehead skin tone of 52 participants. We compared measurements in L*a*b color space and in individual typology angles (ITA). We observed statistically significant correlation between methods, including in specific color space components (L* and ITA). Between the device measurements, we observed discrepancies in ITA values. Such discrepancies, together with a lack of standard or ground truth method, show a need for further research into skin tone measurement. We suggest in the interim that research and clinical work adopt protocols that take current methodological limitations into consideration, for example through the parallel use of different methods if applicable. Further work is needed to develop validated, reliable and consistent skin tone measurement tools.