Repeatability of experiments.

<p>Standard deviation (n = 6) for normalized gray value and time to achieve a normalized gray value of Exp. 1 (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0041677#pone-0041677-t001" target="_blank">Table 1</a>). The horizontal lines labeled with 100%, 50%, 25% and 12.5% represent the normalized gray values from a calibration experiment with according blood model concentrations.