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Sharpen selectively



You can sharpen parts of your image by using a mask or a selection. This is useful when you want to prevent sharpening in certain parts of your image. For example, you can use an edge mask with the Unsharp Mask filter on a portrait to sharpen the eyes, mouth, nose, and outline of the head, but not the texture of the skin.

Using an edge mask to apply the Unsharp Mask only to specific features in an image

Sharpen a selection

  1. With the image layer selected in the Layers panel, draw a selection.
  2. Choose Filter > Sharpen > Unsharp Mask. Adjust the options and click OK.

    Only the selection is sharpened, leaving the rest of the image untouched.

Sharpen an image using an edge mask

  1. Create a mask to apply sharpening selectively. There are many ways to create an edge mask. Use your favorite method, or try this one:

    • Open the Channels panel and select the channel that displays the grayscale image with the greatest contrast in the document window. Often, this is the green or the red channel.

      Selecting a channel with the greatest contrast

    • Duplicate the selected channel.

    • With the duplicate channel selected, choose Filter > Stylize > Find Edges.

    • Choose Image > Adjustments > Invert to invert the image.

      Find Edges filter applied and image inverted

    • With the inverted image still selected, choose Filter > Other > Maximum. Set the radius to a low number and click OK to thicken the edges and randomize the pixels.

    • Choose Filter > Noise > Median. Set the radius to a low number and click OK. This averages the neighboring pixels.

    • Choose Image > Adjustment > Levels and set the black point high to get rid of random pixels. If necessary, you can also paint with black to retouch the final edge mask.

      Setting the black point high in Levels to eliminate random pixels in the edge mask

    • Choose Filter > Blur > Gaussian Blur to feather the edges.

      Important: The Maximum, the Median, and the Gaussian Blur filters soften the edge mask so that the sharpening effects blend better in the final image. Although all three filters are used in this procedure, you can experiment using only one or two.
  2. In the Channels panel, Ctrl-click (Windows) or Command-click (Mac OS) the duplicate channel to make the edge mask a selection.
  3. In the Layers panel, select the image layer. Make sure the selection is still visible on the image.
  4. Choose Select > Inverse.
  5. With the selection active on the image layer, choose Filter > Sharpen > Unsharp Mask. Set the desired options and click OK.

    To view your results, select the RGB channel in the Channels panel and deselect the selection in the image.

    You can create an action to conveniently apply all the steps in the procedure.