Power-law spectrum F_ν ∝ ν⁻² absorbed by a distribution of column densities. The distribution Θ is drawn from a lognormal with avg_Θ = 21.0 (upper left panel), 22.0 (upper right), 23.0 (lower left), and 24.0 (lower right) dex [cm⁻²]. Distributions for different std_Θ are also shown in each panel: std_Θ = 0.5 (dot-dashed green line), 0.3 (solid red), 0.2 (dotted yellow), 0.01 (solid cyan). The dashed blue line shows an absorbed flat spectrum with the same normalization, absorbed by N_H = avg_Θ in each plot.