EW(1318 nm) (plots a,c,e) or EW(1318 nm)/E(B – V) (plots b,d,f) plotted against N(H I), N(H₂) and f(H₂). Stars with emission lines near 1318 nm were excluded. Blue circles: CRIRES data with N(H I), N(H₂), f(H₂) from the literature. Red squares: CRIRES data with H I calculated from the 5780 DIB and N(H₂) from CH. Purple pentagons: X-shooter with N(H I), N(H₂), f(H₂) from the literature. Outlier HD 105071 is labelled.