Increasing Ambient Occlusion Shadowing

I can darken them a little by changing the colour of the ambient light (in OPtions>ViewModes>SpecificViewMode>LIghting Scheme) to Black, and the colour of the shadows to black, but there’s of course no colour darker than that and I still find the shadows too subtle.
These are the only settings I can find to influence the darkness of the AO shadows.
Any suggestions?

there is not direct option for this in Rhino (yet), but a test command can help you with that. Try:
and play with Radius and Intensity.

Apart from that two other things influence the intensity of the AO, which is a bit odd but it may help as well:

  1. lens length (the wider lens, the less dark shadow)
  2. target distance from camera (the further the target, the darker the AO shadow)