Top. SED of a source in the ℓ = 30° field. The upper limit at 70  μm is shown and black line shows the best-fit modified blackbody, whereas gray lines show the 68% confidence envelope of modified blackbody models from Monte Carlo simulations. Also shown are the best-fit parameters from the SED fit: temperature, T, total luminosity, L, dust mass, M_dust, dust emissivity index, β, and dust optical depth, τ.Bottom. Another Hi-GAL clump with a more peculiar shape of the SED, due to the use of Eq. (1) instead of the optically-thin approximation.