Observed GTC/CanariCam (this paper) and Herschel/PACS (from Müller et al. 2014) divided by model fluxes for the two extreme cases with roughness slope angles rms = 0.0 (upper) and 0.9 (lower). Notice that observed-to-modeled fluxes of the GTC/CanariCam data are particularly sensitive to roughness and worsen for larger roughness, which led us to favor the solutions with low surface roughness in our analysis.