In this particular case, it is mainly the render. All I did here in postwork, where her eyes, and few highlights on her skin to make them a little bit more pop . As well as a bloom effect on the skull.
But I play heavily with the exposure triangle in testrenders before I do the final shot. (ShutterTime 1/45, f/stop 22, ISO 400.) I'm also using spectral rendering, which helps to make the colors look more natural in different light set ups.
For darker scenes I normally don't reduce the light in postwork, but increasing it. It is far more easier to amplify the light in poswtwork than reducing it. The easiest way to pop a dark scene is, to render it darker than intended and than duplicate the processed image in an additional layer and set its Mode to "screen".After that, play with the opacity of the screen layer.