Variables	Sources of variation¹			Mean	Contrast (L)²
Variables	T	L	T × L	Mean	C × W	Linear	Quadratic
Thickness	0.1304	0.0001	0.3652	0.278	0.0001	0.0001	0.0035
L*	0.0001	0.0001	0.0242	86.2	0.0001	0.0001	0.0002
a*	0.0001	0.0001	0.0001	−0.78	0.0001	0.0037	0.0001
b*	0.0001	0.0001	0.0001	10.3	0.0001	0.0001	0.9601
Chroma	0.0001	0.0001	0.0001	10.3	0.0001	0.0001	0.1103
Hue angle	0.0001	0.0001	0.0001	94.4	0.0001	0.0002	0.0001
Opacity	0.0001	0.0001	0.0001	59.1	0.0001	0.0001	0.0075
ΔE	0.0001	0.0001	0.0001	8.03	0.0001	0.0001	0.0001