The paper presents a method to measure dust reddening using the colors of stars with spectra from the Sloan Digital Sky Survey (SDSS). The authors measure reddening as the difference between the measured and predicted colors of stars, derived from stellar parameters obtained from the SEGUE Stellar Parameter Pipeline (SSPP). The uncertainties in these measurements are 56, 34, 25, and 29 mmag in the colors $u-g$, $g-r$, $r-i$, and $i-z$, respectively. The spectrum-based reddening measurements confirm earlier "blue tip" reddening measurements, finding reddening coefficients that differ by $-3\%$, $1\%$, $1\%$, and $2\%$ in $u-g$, $g-r$, $r-i$, and $i-z$ from those found by the blue tip method, after removing a $4\%$ normalization difference. These results prefer an $R_V = 3.1$ Fitzpatrick (1999, F99) reddening law over O'Donnell (1994) or Cardelli et al. (1989) reddening laws. The authors provide a table of conversion coefficients from the F99 reddening law and the $14\%$ recalibration of the Schlegel, Elston, and Finkbeiner (1998, SFD) dust map. The paper also discusses the implications of these results for the reddening law and concludes with a discussion of future investigations into the three-dimensional distribution of dust.The paper presents a method to measure dust reddening using the colors of stars with spectra from the Sloan Digital Sky Survey (SDSS). The authors measure reddening as the difference between the measured and predicted colors of stars, derived from stellar parameters obtained from the SEGUE Stellar Parameter Pipeline (SSPP). The uncertainties in these measurements are 56, 34, 25, and 29 mmag in the colors $u-g$, $g-r$, $r-i$, and $i-z$, respectively. The spectrum-based reddening measurements confirm earlier "blue tip" reddening measurements, finding reddening coefficients that differ by $-3\%$, $1\%$, $1\%$, and $2\%$ in $u-g$, $g-r$, $r-i$, and $i-z$ from those found by the blue tip method, after removing a $4\%$ normalization difference. These results prefer an $R_V = 3.1$ Fitzpatrick (1999, F99) reddening law over O'Donnell (1994) or Cardelli et al. (1989) reddening laws. The authors provide a table of conversion coefficients from the F99 reddening law and the $14\%$ recalibration of the Schlegel, Elston, and Finkbeiner (1998, SFD) dust map. The paper also discusses the implications of these results for the reddening law and concludes with a discussion of future investigations into the three-dimensional distribution of dust.