I will be doing High Pass sharpening, Since I want to keep the fine details, I’ve used a pixel radius of 3.
Next, desaturate the layer, this can be done quickly by pressing Ctrl+Shift+U. This to avoid weird color casts but also to gain as much quality as possible in the sharpening afterwards.
Because I want to avoid the noise, I will reduce the noise levels on the high pass layer. A simple noise reduction process will do. Don’t overdo it however you don’t want the details getting soft and resulting in the opposite effect.
Once that is done, I am going to change the blending mode to Vivid Light (I prefer it over the others since the effect isn’t too strong), but you can use Overlay, Soft Light, Hard Light or Linear Light, depending on your preference and situation.
By double clicking on the high pass layer (and away from the layer title), or clicking on the layer FX button in the layers pallette, the blending options dialog will open. On the bottom, you’ll see the blend if section which has one dropdown menu and two sliders. Keep in mind that it doesn’t have to be a high pass layer, this works with any layer type, even if it has some vector shapes you want to blend in with something else.
Then you see
Because I am interested in protecting the bottom layer, I will be working with the Underlying Layer slider.
YUou can choose to do the sharpening in the shadow areas or the highlights.
In order to do so, limit the slider to the one side or the other. This will depend on the lighting on the picture so it is a matter of taste, move the slider bars towards the tonal range you want sharpened.
Notice that you can create different sharpening strengths and radiuses for different tonal ranges this way to achieve more controlled and accurate sharpening.
Now, in order to avoid harsh transitions, the sliders can be split by option+click. In doing this, you can feather the effect for smoother transitions.
If there are some areas still affected, you can always add a layer mask and brush away the parts you don’t want affected. If you master this process, however, you’ll rarely need the masking.