Effective disk radius versus absolute g magnitude for the EFIGI disk (or exponential) components. The color of the points correspond to groups of Hubble type. Dashed gray lines are iso-μ₀ lines, of slope −0.2, which for an exponential profile corresponds to a disk luminosity scaling as . They allow to see that disks span ∼6 dex in central surface brightness at all magnitudes. The solid lines are ODR fits: three linear models for disks of types E-cD, S0-Scd and Sd-Im, in purple, red and blue respectively, whereas the black line is the second degree polynomial fit of log h_e as a function of M_disk, g for all disks. The size–luminosity relation is close to an iso-surface brightness growth for lenticulars as well as early and intermediate spirals, but there is a tail of faint disks for (dimmer) late-type spirals and irregulars with a larger size than earlier spirals at these faint magnitudes, for M > −19.