Table 2.

The colour properties of the dye I-WB under UV exposure.

Film	L*	a*	b*	C*	h*	ΔE*	ΔC*	Δh*
dye I-APU standard	70.0 ± 0.2	9.5 ± 0.2	5.4 ± 0.1	10.9 ± 0.2	5.8 ± 0.05	–	–	–
dye I-APU after 16 h	72.2 ± 0.1	7.7 ± 0.1	− 3.9 ± 0.1	8.6 ± 0.2	5.8 ± 0.05	9.7 ± 0.2	2.3 ± 0.2	9.2 ± 0.1
dye I-APU after 44 h	77.3 ± 0.2	5.0 ± 0.1	− 3.0 ± 0.2	6.2 ± 0.2	5.8 ± 0.05	12 ± 0.2	4.7 ± 0.2	8.3 ± 0.1
dye I-APU after 86 h	78.0 ± 0.2	4.8 ± 0.2	− 3.1 ± 0.1	5.7 ± 0.2	5.7 ± 0.05	12.3 ± 0.2	5.2 ± 0.2	8.0 ± 0.1
dye I-APU after 209 h	79.8 ± 0.2	2.1 ± 0.2	− 2.6 ± 0.1	3.4 ± 0.2	5.4 ± 0.05	14.7 ± 0.2	7.5 ± 0.1	7.9 ± 0.1
dye I-APU after 302 h	80.5 ± 0.1	1.5 ± 0.1	− 2.0 ± 0.2	2.5 ± 0.2	5.4 ± 0.05	15.1 ± 0.2	8.4 ± 0.2	6.9 ± 0.1
dye I-APU after 414 h	81.9 ± 0.2	0.6 ± 0.1	− 1.6 ± 0.2	1.7 ± 0.2	5.1 ± 0.05	16 ± 0.2	9.2 ± 0.2	5.5 ± 0.1