Rendering and Post work
For this scene, I could get away with quite low settings for final gathering as the scene has quite dirty/messy surfaces, so gi artifacts wont be very noticeable, the min/max radius controls the size of samples, [this probably isn't technically correct, that's how I think of it] so if the gi isn't looking detailed enough this is probably why.For the anti alias settings I used 1,16 which should be plenty, and the mitchell filter is a bit sharper than the default. Those are the main settings to worry about for this type of scene in MR so far I have found.
Post work in Photoshop
I use this particular technique quite often, and always do a bit of photoshop work after rendering from max, even if it is just adjusting brightness/contrast/saturation.
to start off with here is the render straight into ps
Duplicated the layer, leaving the original one incase it needs starting again from there. I decided the image wasn't quite sharp enough so I used the un sharpen mask filter and fiddle with the different sliders until I was happy
Duplicate that layer, this one is going to be overlayed on top of the base layer that has been sharpened, I used a maximum filter on it to expand the highlights a bit.
then use the gaussian blur filter, just enough so it is all smoothed out and there isn't any of the jagged bits from the maximum filter
next is changing the layer blending for the top layer, I chose overlay on this one, although soft light/hard light/lighten are also ones that I use quite often, then adjust the opacity to whatever looks best. Its hard to explain what each blending mode does, [although they are in the manual] playing around with different ones with different opacity's is the best was to find out.
For the last step, add hue/saturation layers for both layers in use. If you ALT+click in between layers, you can set an adjustment layer to only effect the one is it attached to, as you see in the image above how the two hue/sat layers are both inset and have an arrow pointing to the layer they effect.