Type of SFR indicator used in each SFR− M_∗ bin. Red colours correspond to SFR− M_∗ bins in which all galaxies have a FIR (i.e., PACS/SPIRE) detection, i.e., galaxies of the first step of the “ladder of SFR indicator”. Green colours correspond to SFR− M_∗ bins in which galaxies are not detected in the FIR but are detected in the mid-infrared, i.e., galaxies of the second step of the “ladder of SFR indicator”. Black colours correspond to SFR− M_∗ bins in which galaxies are only detected in the optical/near-infrared, i.e., galaxies of the third step of the “ladder of SFR indicator”. Short-dashed lines on a white background show the MS of star formation (see Sect. 2.7).