Residuals of the P–T profiles retrieved for the 4 – 18.5 µm, R = 50, LIFESIM S/N = 10 Venus-twin spectrum (opaque H₂SO₄ clouds) relative to the retrieved median P–T profile. Color-shaded areas indicate percentiles of the P–T residuals. If the model includes clouds, the gray shaded regions indicate percentiles of the retrieved cloud-top pressure. The solid black line, the orange circular marker, and the red square marker represent the true profile relative to the retrieved median (for the transparent H₂SO₄ cloud and cloud-free models, we cannot plot the true surface and the P–T profile at pressures higher than retrieved surface pressure). In the top right, we plot the 2D P₀-T₀ posterior (if retrieved; otherwise . Each panel summarizes the result for one of the four different forward models (see Sect. 2.3.2). From top-left to bottom-right: Opaque H₂SO₄ clouds, transparent H₂SO₄ clouds, opaque H₂O clouds, and cloud-free.