We have carried out a quantitative comparison of the dispersion quality for ultracentrifuged and diluted surfactant-stabilised single walled nanotube dispersions. We have characterised these dispersions at a fixed concentration of similar to 30 mu g mL(1) by absorption and photoluminescence spectroscopy as well as by statistical atomic force microscopy. Both the ultracentrifuged and the diluted samples contained significant quantities of bundles as well as individual nanotubes. The ultracentrifuged sample contained similar to 4 times more individualised SWNTs than the diluted sample with partial concentrations of individual nanotubes of 4.8 and 1.1 mu g mL(1), respectively. (C) 2009 Elsevier B.V. All rights reserved.