The color analysis of the fiber samples was performed with a
colorimeter (Minolta, CR400, Japan) following the color system of
the CIE-L*a*b*, where the L* value (brightness) ranges from black
(0) to white (100), the chroma a* value ranges from green (60) to
red (þ60) and the chroma b* value ranges from blue (60) to yellow
(þ60). The chroma C* value and the hue angle (hab), referred to
as the color system CIELCh according to Minolta (1993), were
calculated by Eqs. (1) and (2)