Deviation from ionisation balance as a function of the atmospheric parameters. Dwarf stars from Paper I are plotted in blue, and CEMP stars are highlighted with dark contours. The symbol sizes are inversely proportional to log ɡ. The red lines in the top and bottom panels connect medians computed in equally spaced bins of T_eff and log ɡ, respectively; medians and bin sizes are indicated in the plots. The vertical bars correspond to 1σ standard deviations; the corresponding values are indicated in the plots as well.