Comparison of plage areas reconstructed from sunspot areas and sunspot group number series. Panel a: reconstructed plage areas from MEA20 sunspot area series (black) and the CEA17 GSN series (green) along with the CEA20 plage area composite (blue). Shown are annual median values (solid lines) along with the asymmetric 1σ intervals (shaded surfaces) only for the period covered by CEA20 plage area composite. The numbers below the curves denote the conventional SC numbering and are placed at SC maximum periods. Panels b–c left: residual areas in fractions of the disc between the CEA20 plage area composite and the plage areas reconstructed from the MEA20 sunspot areas (panel b) and the CEA17 GSN series (panel c). The red dashed line denotes 0 plage area differences. Panels b–c right: distributions of the differences in bins of 0.001 in fractional areas.