Top: both [CI](2−1)/(1−0) (red) and ¹²CO(7−6)(4−3) (blue) flux ratios are degenerate with respect to H₂ kinetic temperature and density, but the intersection of the two degenerate curves defines a unique value for both. Bottom: with the H₂ temperature and density from the left panel, the flux ratios [CI](1−0)/¹²CO(4−3) (red) and [CI](2−1)/¹²CO(7−6) (blue) can be used to find neutral carbon and carbon monoxide column densities. Curves are shown for ¹²CO(4−3)/[CI](1−0) ratios of 1.2 to 0.6 (left to right; the flux ratio of 0.8 is marked by a thicker line) and for ¹²CO(7−6)/[CI](2−1) ratios of 8, 6, and 4 (thick line).