Tutorial: How to Sharpen Photos with the Unsharp Mask

March 14, 2011 · 0 comments

in Photoshop,Resources,Tutorials

So, today we’re talking Image Sharpening, and it’s not as scary or difficult as you might think!

Sharpening is one of the tools that gets misused the most… Sharpening needs to be used in moderation, otherwise your image will look over sharpened and have distorted pixels. Most importantly, sharpening an out-of-focus image will not make it sharp, it will just look worse. One of my lecturers once said, “Photoshop can not make a bad photograph good…”

How does Sharpening work?

Sharpening exaggerates the contrast of edges, to give the illusion of definition.

How do I Sharpen my images?

There are several ways to sharpen images:

Sharpen Filter: You can use the Sharpen Filter to sharpen the entire image in one click.

Unsharp Mask: You can use the Unsharp Mask for more control and to adjust the level of sharpness.

High Pass Filter and Smart Sharpen

Tips for Sharpening

When Sharpening, always remember… Less is more! I also recommend, instead of sharpening the entire image, only sharpening the areas that need it.

Always leave Sharpening for last, after you have sized the image. It’s also a good idea to keep a copy of the image that has not been Sharpened, in case you need to resize the image at a later stage.


Understand the settings

Essentially, the Unsharp Mask emphasizes the edge contrast of details in 3 ways:

Amount: This controls the amount of contrast applied. Increasing the Amount, will make light areas lighter, and dark areas darker.

Radius: This defines the area to be sharpened. A small radius will only sharpen the pixels close to the edges, while a high radius will sharpen a larger area of pixels surrounding the edges. If you notice halos around the edges, this means you have set the radius too high.

Threshold: This limits the amount of sharpening applied, by determining how close the pixels should be in order to be considered “edge pixels”. In areas where there is little difference (such as skin tone) the threshold can be adjusted to exclude these areas from being sharpened.

These settings will vary with each image, and image size plays a very important role. The rule of thumb is, the bigger the image size, the more you can increase the values of the settings.

This tutorial uses Adobe Photoshop CS5.

Step 1: Open your image in Photoshop, and duplicate the layer by pressing Command J (Mac) or Ctrl J (PC).

Step 2: Using the Lasso Tool, select the areas that need sharpening.

Step 3: Click Filter > Sharpen > Unsharp Mask. The box that appears will show you a preview of the selected area, and the settings to adjust the sharpness. Adjust these 3 settings until you are satisfied with the outcome. The result should be a more defined image, free of halos, graininess and distorted pixels.

Once you are happy with the adjustments, click OK and save the image.

Here is a side-by-side comparison:

The difference should be subtle, and realistic looking.

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