Image Sharpening Using the Unsharp Mask Filter

The Unsharp Mask, contrary to its name, actually sharpens your photo by elevating the contrast along the image’s edges. It’s pretty heady stuff that we don’t need to go into, all we need to know is that it works!

Step 1

Open up the image you want to work on, press Command-1 (PC: Control-1) or double-click the Zoom Tool to bring the image to 100%. You want the image to be at least 100%, so you can accurately and effectively see what the sharpening is doing, and know the threshold of the dreaded “halo effect.”

Step 2

Next click on the background layer, Right Click (or hold down command to bring up the Menu) and zip over to Convert to Smart Object. Then dive in to FILTER> SHARPEN> UNSHARP MASK. In the Unsharp Mask preview window, reposition your image so you can see the most prominent details.

Step 3

You have three variables to manipulate: Amount, Radius and Threshold. “Amount” is how much sharpening you’re doing, “Radius” is the reach of the filter, in terms of how far from an edge the sharpening extends. The value determines the number of pixels surrounding the edge pixels that get affected by the sharpening. So remember, the larger the Radius value, the wider the edges and the more obvious the sharpening… which is a big no-no. “Threshold” is the Strong Safety, so to speak, as in it protects you from other miscalculations or overzealousness!

Step 4

Set the Amount slider to a value to determine how much you want to increase the pixel contrast, between 100 and 200. The actual Amount of sharpening depends on the size and resolution of your image; so you can get away with an Amount of 100% on most images, but for hi-resolution images, you might want to try more than 130% to get a noticeable effect. Next increase your Radius to somewhere between 1 and 2 pixels, so you just start to see the halo around the edges (the telltale sign of manipulation… which you don’t ever want), then dial Radius back so the halo magically fades away… that’s your boundary, your sweet spot.

Step 5

Now that you have the sweet spot, lower the Amount by around 20 to 30 percentage points. For the final tweak, use the Threshold slider. Threshold sets a frontier in which the sharpening takes hold or doesn’t, and that’s based on the tonal value of the pixels that you’re looking to affect. The value establishes how different the sharpened pixels will be from the surrounding area before those pixels are affected by the filter. This is one of those “seeing is believing” options, so try between 2 and 20 for starters and then raise the Threshold to soften the sharpening until the image looks fabulous. Next, click on the Preview to see the before and after images. Since sharpening brings out some noise in the photo, you’ll want to change the blend mode to counteract this side effect; so change the Blend Mode on the layer you’re sharpening to Luminosity. This projects the image’s value, which is all important when looking to get rid of noise.

Before & After Image Sharpening