Averaged scattered-light disk contrast plotted against disk fractional IR luminosity for measurements obtained with SPHERE/IRDIS in the broadband H (blue and orange markers) and J (red markers) filters, as well as with HST/STIS (black markers), as shown in Fig. 24. The averaged scattered-light contrasts were calculated from measured either polarized or total scattered fluxes, as indicated in the figure legend, and assuming an asymmetry parameter g = 0.7 and a maximum polarization fraction p_max = 0.3 for all disks. Marker shapes reflect disk inclinations. The black solid line indicates the 1:1 relation.