Normalized equivalent widths of the DIBs at 5780, 5797, and 6284 Å vs. the intensity of the ambient radiation field (I_UV) inferred from the rotational excitation of H₂. Circles denote LMC sight lines; triangles denote SMC sight lines; all other symbols are for Galactic sight lines (see Fig. 8). While the DIBs are generally weaker in the LMC and SMC, no significant trends with I_UV are apparent in any of the three galaxies.