Spatial variations of the dust properties per gas nucleon, relative to the average values obtained at low N_H, in the (1−2.2) × 10²¹ cm^-2 interval for N_{H γ} (left column), and in the (0.4−2) × 10²¹ cm^-2 interval for N_{H mλ} (right column). As in the previous figure, the total gas is measured by N_{H γ} on a 0.̊375 pixel grid (left) and by N_{H mλ} on a 0.̊125 pixel grid (right). Colours saturate for ratios below 0.5 and above 3.2.