Distribution of σ_DIB for DIBs λ862.1 and λ864.8 (top and bottom, respectively). The dashed red and green lines correspond to the “best range” and the “secondary range” of σ_DIB defined in Sect. 4.1 for the DIB QF, respectively. The distribution of the full DIB-Spec results (235 428 voxels) is shown in the left panels, while the right panels show a quality-controlled sample with S/N > 100 and 𝒟 > 3R_C (see Sect. 4.2). The latter criterion implies QF values of 0 or 2. The number of detected DIBs and the percentage after the quality control is indicated as well.