Learn how to sharpen an image on the edges only with this Photoshop tutorial. Ordinary sharpening methods sharpen the entire image including the areas that you don’t want sharpened such as the skin, clouds, etc. But with this tutorial, you’ll learn how to sharpen only on the edges so that artifacts don’t appear.
Photoshop Tutorial Preview
Step 1
First go to File> Open, browse for a picture and then click OK.
Step 2
We begin by duplicating the layer. The top layer will have the sharpened version of the image and the bottom (Background) layer will have the original untouched image with its default sharpness. To duplciate the layer, press Ctrl+J or go to Layer> Duplicate Layer.
Step 3
Before we start sharpening, we need to add a layer mask. A layer mask will let us filter out where the layer gets shown so that we can choose which parts of the image to show the sharper layer. To add a layer mask, go to Layer> Layer Mask> Reveal All.
Step 4
You should now have a layer mask and it should be selected. You can tell if it’s selected or not by checking for a white outline around the layer mask thumbnail. Once you have the layer mask selected, go to Image> Apply Image. Here, just use the default settings and click OK.
Step 5
Now you can see that you applied a copy of the image into the layer mask. Between the layer mask and the layer thumbnail, you should see a symbol that looks like a chain. Click on that and it’ll unlock the layer mask from the layer. What this does is let you modify the layer mask without anything changing on the actual layer. For example, if you had it linked with the chain icon showing, if you move the layer mask, the layer will move too. But when you unlink them, when you move the layer mask, the layer won’t move.
Step 6
Now here’s the key part to this sharpen edge technique. The Find Edges filter. This filter will create a sketch of the outlines. So lets apply this filter. Go to Filter> Stylize> Find Edges. Your layer mask should now have an outline.
Step 7
In the layer mask, the white areas mean that the layer will show and the black areas mean that it won’t show. So right now, we have the outline as black meaning that the edges won’t show. We want the opposite so we’ll invert the layer. To do this, press Ctrl+I or go to Image> Adjustments> Invert.
Step 8
Now that we have everything setup, we can sharpen the layer. Click on the layer thumbnail to activate the layer and deselect the layer mask. Now go to Filter> Sharpen> Smart Sharpen. If you don’t have Smart Sharpen, you’re probably using an older version of Photoshop without it but you can use the Unsharp Mask instead that you can find in Filter> Sharpen> Unsharp Mask. With the tool, sharpen the image. Here’s what the Smart Sharpen filter looks like. When I sharpen it, the filter preview shows that there are lots of halos and the skin becomes sharpened too. But if you move that window to the side and look at the document window image behind it, you can see that it only sharpened the edges. Here you can see the big difference between the normal sharpening method and the sharpen with edge mask method by comparing the image on the sharpen window and the image in the Photoshop document window.
Step 9
Here’s what the image looks like before. It’s OK; good enough for showing on the web but not really sharp enough for print.
Final Results
And here’s what it looks like after sharpening the edges only. Notice how her facial hair isn’t sharpened but the frame of her class and eyes are.
