Opacity profile of a 1 M_J planet with T_eq = 200 K at about 4.5 Gyr. The pressure-temperature conditions were from the baseline model using the Freedman et al. opacity (blue line). The orange line includes grains with a scaling factor f_grains = 0.1. The effect of a single optically thick cloud deck at 10 bar with δ_c = 10 and κ_clouds,0 = 1 cm²/g is shown in the green line. The dashed purple line illustrates how an opacity window could be created due to a lack of alkali metals.