Top: best χ² for β Pictoris b SED (black dots) with (red triangles) and without (blue stars) clouds after radius and mass selection. Thick lines indicate the widths of the filters. CH_4S,1% and NB 4.05 are very narrow filters, less than the width of plotted observation points. Bottom: difference between synthetic and observed fluxes divided by the uncertainty on the observed flux. The two horizontal lines indicate the ±1 standard deviation level.