Comparison of temperature scales for [Fe/H] = 0 for standard filters (Bessell 1990; Maíz Apellániz 2006), 2MASS (Cohen et al. 2003), and Gaia filters. Upper panels: comparison with the empirical temperature scales from Ramírez & Meléndez (2005) (blue solid and red dashed lines) and Casagrande et al. (2010) (black dotted lines). Middle panels: comparison with the results from Casagrande & VandenBerg (2014, 2018a,b); the Gaia filters are from Evans et al. (2018). Lower panels: comparison with the 3D models from Chiavassa et al. (2018); the Gaia filters are those from Jordi et al. (2010). Our BCs are derived from ATLAS9 models.