Synthetic UV spectra of NGC 6826 (upper two panels) and IC 418 (lower two panels) calculated with the stellar parameters determined by the UV analysis, compared to the observed UV spectra. The first panels in the upper and lower part show unclumped models. The overall fit to the observed UV spectra is generally very good, although the He iiλ 1640 line is not reproduced too well. The second panels in the upper and lower parts show the same models, but with a clumping factor of f_cl = 4. Most of the UV spectrum is not affected, except for a few lines from subordinate ionization stages (such as P vλ 1118, C iiiλ 977, and H iλ 1216). In particular the match to the observed He iiλ 1640 line is now almost excellent.