Table 2.

Results from a direct current OptoBeat skin tone experiment.

Skin tone type	Blue value	Red value	Ratio of ratios	Difference from type 5, %	Difference from type 3, %	Difference from type 2, %
5	0.8	0.61	0.76	N/Aa	19.3	16.6
3	1	0.94	0.94	19.3	N/A	3.3
2	0.65	0.59	0.91	16.6	3.3	N/A

^aN/A: not applicable (data are compared to themselves).