HiBAL, and LoBAL classes in the rest of our analysis.

The $P$-fit (top spectrum in Figs. \[fig:fig3\]–\[fig:fig5\]) was achieved by changing only the spectral index $\alpha_P$ of each of the HiBAL and LoBAL composites. From the $P$-fits, one could make an argument for BALQSOs simply having redder spectral indices than nonBALQSOs. Similarly, applying only the SMC ($R$-fit) reddening law to the composites (second spectrum in Figs. \[fig:fig3\]–\[fig:fig5\]) suggests that dust-only reddening might just as adequately account for the color differences between BALQSOs and nonBALQSOs. Finally, the $RP$-fit difference spectra are plotted as the third spectrum in each of Figures \[fig:fig3\]–\[fig:fig5\], using spectral indices and relative reddening from Table \[tab:tab1\]. As with both of the previous fitting procedures, the $RP$-fit does a reasonably good job of correcting for the color differences between the BALQSOs and the nonBALs.

For wavelengths longer than about $1700\,{\rm \AA}$, each of the three reddening corrections to the BALQSOs reproduces the continuum of the nonBALs reasonably well. Thus, it is difficult to use this analysis alone to answer the question posed above regarding the nature of the reddening in BALQSOs. Expanding our wavelength baseline via UV and near-IR spectra of our objects would clearly be valuable in 