The standard sharpening techniques like Sharpen, Sharpen Edges and Smart Sharpen are useless when sharpening faces. It works ok with hair, but the last thing you want to do is sharpen skin, especially women’s skin. It is the fastest way you will get negative feedback on your images if you over sharpen women’s faces. Why do you think there is so much makeup available, it is to soften the skin not give it a crackling effect.
We will be using Unsharp Mask in this tutorial and sharpening an inverted red channel on top of a Luminosity blend mode. Well that is the super condensed summary version. Lets start off with an image I got from Public Domain Pictures. I did not download the full sized image but you can do it yourself and get better results.
Step 1: Open the image you like to edit in RGB mode.

The image is ok, but it lacks bite or as other photographers call it, “pop”.
Step 2: Create a duplicate layer background by pressing CTRL-J.

The duplicate layer is on top and the background layer is on the bottom. You can change the name of the new layer, but I will keep it as it is. It is a good idea to sometimes change it to a name that you understand, especially if you have changes some properties on it.
Step 3: With the top layer selected, click on the Channels tab

Step 4: Invert the red channel by pressing CTRL-I.

Now don’t worry, you still have the original background layer so if you mess this layer up, just delete it and start over. The red channel must still be selected, don’t deselect it.
Step 5: Select from the top menu <Filter><Sharpen><Unsharp Mask>

In the boxes type in the following: Amount: 450%, Radius: 1.3px and Threshold: 0. When using high Amount values, try and use low Threshold levels. The best is to play around with the numbers. When finished typing in the values press <OK>.
Step 6: Invert the image again by pressing CTRL-I.
Step 7: Select from the top menu <Filter><Sharpen><Unsharp Mask>

When done, click <OK> to apply settings. This is all done on the top layer and on the red channel. Remember, it is not inverted anymore. You should see a standard grey image of your model.
Step 8: Select layers palette and change top layer blend mode to Luminosity.
You must change the top layer to Luminosity otherwise you will see red highlights throughout the image.
Step 9: Admire your work.
