Comparison between ECS and model SED for SPSS with colour index G_BP − G_RP respectively equal to (from left to right, from top to bottom) 0.06, 0.27, 0.83, 1.03, 1.07, 1.35, 1.68, 2.26, and 2.65. ECS flux at wavelengths λ < 400 nm is systematically lower than expected for bluer sources and higher than expected for the redder ones. The colour convention and symbols are the same as in Fig. 32.