Histograms of the difference between the temperature computed by SPECIES, and those using the colour relations from C10. The lines correspond to Gaussian distributions adjusted to the histograms, with mean values listed in Table 4. Each colour represents a different instrument: red for HARPS, blue for FEROS, green for HIRES, and orange for UVES. The different panels show the temperatures computed using different photometric colours, mentioned in Sect. 2.