Sharpening images can be a challenging task. One of the issues involved is the choice between sharpening the entire image, or sharpening only the areas that will really add to image quality.
This is a cropped portion of a portrait taken a few weeks ago. It is shown at roughly 100%, or actual pixels. Some very basic adjustments have been made, such as color and contrast. These layers were consolidated into Group 1.

In the next step, I duplicated Group 1. This command is found under Layer > Group Layers. Next, we will duplicate the Group, by selecting the duplicate Group (blue highlight) and
using the command Layer > Merge Group. This merges the underlying layers in the group into one new layer. See the illustration below this one, and note that the group has changed to a normal layer.


I’ll sharpen the layer using a technique which may be new to some. Go Filter>Other>High Pass. Set the intensity to 2.o, and click OK.

Change the blending mode of this layer to Hard Light (see Layer panel).

Now for the best part: First, we are going to create a layer mask which hides this sharpening effect. Select the Layer (blue highlight) and Go Layer>Layer Mask>Hide All.

Next, left click on the layer mask (black box next to the layer thumbnail. You’ll see a highlight, or “picture frame” appear around the layer mask. Select the Brush tool, and set opacity to 100%.
Now, set the brush color to white. The easiest way to do this is to press the “d” key, which will select the default brush colors. You’ll see a black and a white square appear at the bottom of the tool bar. Left click once on the white square to select that color.

Use this brush, set to soft edges and sized appropriately, to paint on the black layer, using the white colored brush. (I have used a red circle to show this brush clearly). This will “reveal” the sharpening you have created on the layer. You should brush over the eyes, eyebrows, mouth, edges of the nose, ears, and if desired, the hair/hairline. Do not brush over the wider skin areas, as these will usually appear to be too sharp, making the portrait unattractive.
You can set the brush opacity to 100% for full effect, or a lesser intensity for less sharpening. You can also change the sharpening layer opacity to a lower amount if you find the sharpening effect is too aggressive. Make a test print, and enjoy! (btw, with a bit of practice this takes < 1 minute).
