Comparison between the 12 μm fluxes interpolated between Spitzer IRAC 8 μm and IRS 16 μm and WISE W3, also showing the W3 S/N (see colour bar at right). The grey dots denote sources below the W3 S/N = 2 threshold chosen in this work. The black solid (dotted) horizontal line marks the median (lowest 5 th percentile) flux for the objects in our sample without performing the quality cuts described in the text. The same holds for the red lines where also the S/N≥2 cut is applied. Although there is a trail of points detaching from the one-to-one relation at low S/N W3 (∼4–5), roughly 95% of our sample has fluxes higher than the threshold where W3 starts to systematically overestimate the Spitzer measurements. The colour-code of the lines is the same as in Fig.A.1.