Interesting experiment Chris.
A couple of observations - I never do any sharpening at the conversion from RAW stage... in fact I do all my post processing and then sharpen at the last step - I find this reduces the occurrence of odd sharpening effects.
The cutting out is I think a big difference, and you may be surprised to learn that I do not use any selection tools to do it. If I explain the technique I use (which I think you will agree is effective) and then you can tell me if this could be replicated in NX... because as you say you could go on chasing stray hairs for ever - with my technique you don't have to
As you point out the key is make the hair not look cut out.
- I go to the channels palate and look at the individual red, green & blue channels to determine which has the greatest contrast between the models hair and the background - usually the blue channel.
- Next I go to calculations and blend the blue channel with itself in multiply blending mode to create a new channel. This has the effect of adding the darkness of the pixel values together so light bits become a little bit darker and dark bits become a lot darker. This makes the stray hairs stand out better.
- I then go to calculations again with the new channel and repeat the step but with overlay mode. This now darkens areas darker than 50% grey and lightens areas lighter that 50% grey.
I now have a mask like this
Vic_mask.jpg which preserves the fine hair detail
Vic_mask_detail.jpg. It is then a simple matter to fill in the centre of the mask with a black brush to get
Vic_mask_final.jpg apply this to the layer, position new background underneath - generated with a Photoshop action - and you have a perfect natural looking cut out in about 5 minutes max
I then work on the eyes, lips, skin tones etc, again using masks generated from the layers using different channels & blending modes depending on what I'm doing. For example I smooth the skin tones through a straight red channel mask and sharpen through and inverted red channel mask, and the highlights in her hair were enhanced through a grey channel mask blended with itself in overlay mode.
The point being that using these masks that you can lighten, smooth, darken etc the parts of the image based on the lightness or darkness of the image itself thereby enhancing the tonal graduations.
There, I've given away my trade secrets
Hope this makes sense - I would be surprised if NX gives this level of control, I may be wrong - because if it did it would become the industry standard.