Table 1: PCA results of colors of SSPs in the high-resolution BC03 model. Each row except the first shows the results for colors of SSPs with the same metallicity. "Percent'' and "Correlations'' are the contribution of PC1 to the total variance and correlations of colors to PC1.

Z	0.0001	0.0040	0.0200	0.0500
	PC1	PC1	PC1	PC1
Percent	99.72	98.33	97.54	94.40
		Correlations
U-K	-0.376	-0.378	-0.379	-0.379
U-H	-0.363	-0.364	-0.365	-0.364
U-J	-0.320	-0.321	-0.323	-0.326
B-K	-0.287	-0.287	-0.285	-0.284
B-H	-0.274	-0.273	-0.271	-0.269
U-I	-0.244	-0.248	-0.243	-0.244
B-J	-0.231	-0.230	-0.229	-0.230
V-K	-0.217	-0.214	-0.214	-0.215
U-R	-0.202	-0.207	-0.204	-0.205
V-H	-0.204	-0.200	-0.200	-0.199
R-K	-0.174	-0.171	-0.175	-0.174
U-V	-0.159	-0.164	-0.165	-0.164
R-H	-0.161	-0.157	-0.161	-0.159
V-J	-0.161	-0.157	-0.158	-0.161
B-I	-0.155	-0.157	-0.148	-0.148
I-K	-0.132	-0.130	-0.136	-0.135
I-H	-0.119	-0.116	-0.122	-0.120
R-J	-0.118	-0.114	-0.119	-0.121
B-R	-0.113	-0.116	-0.110	-0.109
U-B	-0.089	-0.091	-0.095	-0.095
V-I	-0.086	-0.084	-0.078	-0.079
I-J	-0.076	-0.073	-0.081	-0.082
B-V	-0.070	-0.073	-0.071	-0.069
J-K	-0.056	-0.057	-0.056	-0.053
J-H	-0.043	-0.043	-0.042	-0.038
V-R	-0.043	-0.043	-0.039	-0.040
R-I	-0.042	-0.041	-0.038	-0.039
H-K	-0.013	-0.014	-0.014	-0.015