GTC R1000B spectrum of the z = 2.60 QSO GQ 1218+0832 displayed together with the photometry from SDSS, UKIDSS, and WISE, in the u, g, r, i, z, Y, J, H, K_s, and W1 bands (Warren et al. 2007; Wright et al. 2010; Eisenstein et al. 2011). Overplotted is the composite QSO spectrum from Selsing et al. (2016; in blue) and the same composite reddened by A_V = 0.82 ± 0.02 mag assuming LMC-type dust at the redshift of the DLA (in red). Models with and without the 2175 Å dust extinction feature are shown. The inset shows a zoom-in on the blue part of the spectrum around the H I Lyα line from the z = 2.2261 absorber. The red dashed line is the modelled QSO continuum. Also overplotted is the H I DLA Voigt-profile fit, which is included in the dust-reddened QSO composite spectrum, with N(H I) = 10^{21.95 ± 0.15} cm⁻².