In solutions the interaction of ions with solvent often changes the solute properties, which is reflected in the absorption spectrum of the solute (solvatochromism). For some ions a single water molecule has a large effect, while others only display significant changes upon full hydration. Predicting electronic spectra in the presence of solvent is still a challenge for electronic structure theory, so experimental data on prototype solute ions with and without the presence of solvent are important benchmarks. S. Brøndsted Nielsen, J. M. Weber et al. show how solvation affects the electronic spectrum of permanganate on p. 1133.