Sharpening plays an important role in influencing how the human eye interprets a photo and it is the only way to create the illusion of higher definition and detail. Also, much like we use light, color, and composition, it is an extremely effective way to guide the eyes of the viewer to wherever you want them to focus.
The first question to ask isn’t how to sharpen but when to sharpen. Any retouching, compositing, coloring, and any other edits you’ve made should be included in the sharpening process. So make sure that it’s the final step in your workflow just before you export! It’s important to note that you’ll want to resize your images beforehand as well. Resizing an image that has already been sharpened can have adverse effects such as reducing or exaggerating the amount of sharpening.
For example, if you want to upload one of your latest photos to Instagram, first resize your image to 1080 x 1080 pixels (their recommended dimensions for square images). Then go through the sharpening process as normal. Doing this will guarantee that your image quality will be consistent no matter what size your image is or where it will be displayed.
To begin the sharpening process, create a new layer, go to the Image menu, and select Apply Image. Apply Image will take all of the visible layers in your project and merge them together onto the new layer. This will allow you to sharpen your final image (including all of the edits you’ve made) without affecting the originals.
As far as technique goes, there are many ways to sharpen an image. I’ve always preferred the High Pass method which involves converting the new merged image into a Smart Object and then using a High Pass Filter to apply the sharpening effect. Since we’re working with a Smart Object and a Smart Filter, we can always go back to make changes to the radius by simply double-clicking on the High Pass option underneath the layer.
My favorite thing about this technique is just how flexible and precise it can be! If I ever need to make changes to the amount of sharpening I can either duplicate the sharpening layer (for a subtle adjustment), change the radius of the High Pass Filter, raise or lower the opacity, or simply paint with the Brush Tool on the layer mask.
Using Layer Masks, you can apply different levels of sharpening to different parts of a photo. You can have a sharpening layer just for facial features and a second for wardrobe. Create as many layers of sharpening as you need to get the look that you want. Overall, focus your sharpening on aesthetic details in your photo—hair, eyes, jewelry, details in clothing—anything that you want to stand out. Avoid sharpening things that might distract the viewer or bring out details you don’t want to be as noticeable (i.e. pores).
Like most things that we’ll do in Photoshop, sharpening is highly subjective. It’s up to you to determine where and how much to sharpen. And while we use a portrait as our example, this method works across all types of photography! This is a process I’ve developed over several years and it has served me well. So give it a try! I only hope that it helps you figure out your own favorite method that’s best suited for you and your work.