Spatial variations of the amount of reddening per gas nucleon, /N_{H γ}, with the total gas measured by N_{H γ} at 0. °375 resolution (top panel) and its variations relative to the average value of (2.02 ± 0.48) × 10⁻²² mag cm² (bottom panel). Quantities with a tilde are convolved with the LAT response for an interstellar spectrum. The black contours outline the shape of the CO clouds at the level of 1 K km s⁻¹ in W_CO intensity.