With P8, you have the benefit of using IDL, Indirect Diffuse Lighting, which simulates global illumination better than IBL because it calculates photon bouncing on closely located objects.  For IDL to be completely effective, I introduced Bagginsbill's envsphere as a skydome which adds another source of lighting and kept my original Infinite light.  IDL is activated in your renders setting under manual or through Dimension3D's built-in Python Script. 

Now the image shows a more realistic response to the available light in the scene.