  In this comment, we discuss the possibility of imaging the radiative
precursor of a strong shock with a 21.2 nm soft x-ray laser probe and we
analyze the data presented in C.Stehle et al "New probing techniques of
radiative shocks", (Optics Communications 285, 64, 2012) in order to derive
some estimation of the achieved resolution. We show that the presented results
are inconclusive for the existence of a radiative precursor. Furthermore, our
best estimation of cold and warm Xenon VUV opacities tells that 21.2 nm
backlighting would not be able to probe this radiative precursor.
