2.5. Colour measurements
Colour was evaluated by the CIEL*ch system (Colour Quest XE - Hunter Lab, USA). CIEL*ch is a
modification to the CIELAB scale which plots in polar coordinates rather than rectangular ones. The
colour attributes lightness (L*), chroma (C) and hue angle (h) were measured four times on the surface of
the skin. Measurements were performed using 25mm viewing area aperture, D65 illuminant and 10°
observer, according to CIE recommendations [21].