Fig. 5From: Plastics in robots: a degradation study of a humanoid skin mask made of soft urethane elastomerColorimetric values (a*, b*) in two-dimensional CIELab Color Space of the pale pink areas (red 1–5 spots) and yellow areas (black 6–10 spots). The arrows show the change distance between May and October 2019. For the position of sampling spots, see Additional file 1: Fig. S2Back to article page