There are many different techniques you can use to retouch a portrait, and one of the more advanced and powerful out there is frequency separation. This helpful video tutorial will show you what frequency separation is and how to use it to edit a photo.
Coming to you from Julia Trotti, this awesome video tutorial will show you how to use frequency separation to edit a portrait. What makes frequency separation so powerful is that it separates the images into two halves: one with the color and tonality information and the other with the details. This allows you to, for example, edit out blemishes without disturbing the broader light and color or to even out the tonality in your subject's face without destroying the texture. The downside to frequency separation is that it can be too powerful; it only takes a few quick clicks to make your subject look overly artificial and plastic, which led to a bit of a backlash against the technique a few years ago. Nonetheless, with a careful touch, it can be a very effective and useful technique for editing images in an efficient manner. Check out the video above for the full rundown from Trotti.
There are much better articles on frequency separation, even here on fstoppers, so whats the point of this?