  We characterize the temporal profile of the high-order harmonic emission from
ablation plasma plumes using cross-correlations with the infrared (IR) laser
beam provided by 2-photon harmonic+IR ionization of rare gas atoms. We study
both non-resonant plasmas (lead, gold and chrome) and resonant plasmas (indium
and tin), i.e. plasmas presenting in the singly-charged ions a strong radiative
transition coinciding with an harmonic order. The cross-correlation traces are
found very similar for all harmonic orders and all plasma targets. The
recovered harmonic pulse durations are very similar to the driving laser, with
a tendency towards being shorter, demonstrating that the emission is a
\stef{directly} laser-driven process even in the case of resonant harmonics.
This provides valuable input for theories describing resonant harmonic emission
and opens the perspective of a very-high-flux tabletop \textsc{xuv} source for
applications.
