LoBALs are redder than HiBALs, we explore the question of the origin of the reddening. Specifically, we ask whether BALQSOs simply have redder power-law spectral indices or if they are more dust reddened. A combination of both is also possible, as are non-dust-related reddening scenarios; for example Figures 12–14 in (2000) show that redder quasars might simply be observed more face-on, have lower accretion rates, and/or have larger black hole masses, respectively. Since previous work has shown that SMC-like dust reddening might be able to account for the redness of BALQSOs, we adopt that law for our purposes here.

To aid in our analysis, we present the differences between the nonBAL, HiBAL, and LoBAL composite spectra in Figures \[fig:fig3\]–\[fig:fig5\]. In each case we present the difference spectra that result from modifying the BALQSO composites by all three of our fitting methods ($P$, $R$, and $RP$) in addition to showing the unaltered difference spectra (i.e., no changes in spectral index or reddening, but are normalized to unity at 2900 Å). Because the EDR and nonBAL composite spectra are similar, as are the HiBAL+LoBAL and HiBAL composite spectra, we have chosen to use only the composite spectra of the mutually exclusive nonBAL, 