Same as Fig. 3, but over-plotted with a 1500 K isothermal model also containing TiO/VO opacity, producing many strong absorption features. The TiO/VO abundances in the model are from equilibrium chemistry. There is no evidence for TiO/VO in the GTC data, because the model fits with TiO/VO are significantly worse than the alkali-dominated models (see text).