Bolometric corrections BC_K for carbon stars vs. (J – K) colours as compiled from different sources: (i) individual measurements for C stars from Mendoza & Johnson (1965; squares); (ii) the mean relation for C-type giants of Bergeat et al. (2002; full line); (iii) synthetic data based on a representative sub-grid of the hydrostatic COMARCS model atmospheres of Paper I (crosses); (iv) the fit for nearby field C stars provided by Kerschbaum et al. (2010; dash-dotted line); (v) the fit for C star candidates in the LMC derived by Riebel et al. (2012); (vi) individual measurements for field C-type Miras (grey filled circles, blue diamond for RU Vir) taken from Whitelock et al. (2006; Table 6) as well as the corresponding fit given in their Eq. (10) and Table 5 (dashed line). Overplotted are the results for the dynamic model atmospheres of this work. The labels in the upper part mark approximate mass-loss rates Ṁ [M_⊙  yr^-1] for the C-type Miras of Whitelock et al. (2006) as related to a given (J – K)₀ colour in Fig. 7.