Figure 1. Effect of skin redness and blood colour on apparent health of faces.

(A) Untransformed image and images pair showing low (−) and high (+) endpoints of oxygenated and deoxygenated blood colour transforms. (B) Participants increase deoxygenated and oxygenated blood colour to optimise healthy appearance. Initial facial redness (a*) correlates with oxygenated (r = −0.911; p<0.001; R² = 0.83) and deoxygenated (r = −0.831; p<0.001; R² = 0.69) blood colour change applied to optimize health appearance. (C) Endpoints of the two-dimensional oxygenated versus deoxygenated blood colour transform. (D) Two-dimensional colour transform applied to optimize healthy appearance (ΔE mean±SE). (E) Regression lines relating initial face redness to deoxygenated colour change applied to optimise healthy appearance for each participant. (F) Regression lines relating initial face redness to oxygenated colour change applied to optimise healthy appearance for each participant.