De-reddened GTC spectrum of GRS 1758−258 plotted together with HST-NICMOS observations and the irradiated disc model by Luque-Escamilla et al. (2014) labelled as LE14. For comparison purposes, the GTC spectrum has also been plotted in brown scaled by a factor corresponding to variability and absolute flux uncertainty effects with Δm = ± 0.3 mag. The symbol ⊕ denotes the strongest telluric absorption feature.