[UIColor blackColor]と UIColor#colorWithRed:green:blue:alpha: で作った黒って違うんすね

UIColor* black1 = [UIColor blackColor];
const CGFloat* cs1 = CGColorGetComponents(black1.CGColor);
NSLog(@"[1] R:%.1f G:%.1f B:%.1f A:%.1f", cs1[0], cs1[1], cs1[2], cs1[3]);

UIColor* black2 = [UIColor colorWithRed:0.0 green:0.0 blue:0.0 alpha:1.0];
const CGFloat* cs2 = CGColorGetComponents(black2.CGColor);
NSLog(@"[2] R:%.1f G:%.1f B:%.1f A:%.1f", cs2[0], cs2[1], cs2[2], cs2[3]);

2009-03-08 00:16:39.505 Test[688:20b] [1] R:0.0 G:1.0 B:0.0 A:0.0
2009-03-08 00:16:39.514 Test[688:20b] [2] R:0.0 G:0.0 B:0.0 A:1.0

[UIColor blackColor] の方はRGBAじゃなくてモノトーンになってる？色空間ってどうやって指定するんだろう・・・。