Fig. 3.

The absorbance of the microsphere suspension after subtraction of the absorbance of suspension of undyed microspheres. The absorbance above 600 nm is approximately zero. The ripples below 500 nm were due to small difference in the diameters of the dyed and the undyed microspheres. A suspension of undyed microspheres resulted in a better background subtraction than a sample of water. The uncertainty in the peak absorbance value is about 5 %.