Sharpening Using an Edge Mask in Photoshop

Sharpening in Photoshop Part Four

Using an edge mask to sharpen images in Photoshop is handy to sharpen around edges, particularly where detail is required such as rugged landscapes or nature portraits.  The picture below will be used to sharpen around edges to give a cleaner finish.

Image to be used for edge mask sharpening.

Create a Mask for Edge Mask Sharpening.

With the image opened up in Photoshop, switch over to the channels list then select a channel with the most amount of contrast.

Channels will be located just to the right of the layers tab. Only select one channel (red, green or blue) then decide which one would be best to use. For this one, I decided to use the green channel (highlighted) as it has the best result for contrast.

Next is to duplicate this channel.

Duplicate the channel by right-clicking it then selecting duplicate channel.
We now have a duplicated channel. Keep this selected for the next part.

Creating Edge Mask

Working with the duplicate mask, create an edge mask to be used for sharpening.  First, we need to Photoshop to find edges by using Filter > Stylize > Find Edges.

Selecting find edges filter.
How image appears after using find edges.

Inverting Image.

To invert selection, go to Image > Adjustments > Invert.
The result after inverting image.

So far so good, I now have a lovely image that shows edges ready for sharpening.  But it’s not finished yet as we need to thicken the edges.  To do this select Filter > Other > Maximum.

Selecting maximum filter.
It is important to keep a shallow setting here as the lines will be too big. I only set a number to two. When finished click ok.

What I do next is select Median in Filters.  Go to Filters > Noise > Median.

Selecting Median.
Selecting median size. I only chose a little number as three was enough.

Next is to set adjustments levels.  Go to Image > Adjustments >Levels.  What we are doing here is getting rid of any random pixels from our image by setting a high black point.

Selecting levels in Photoshop.
How my image looks after changing mid-tone level.

Next, we need to create a Gaussian Blur.  Go to Filter > Blur > Gaussian Blur.  What I am achieving here is to feather edges on my mask.

Selecting Gaussian Blur.
Setting Gaussian Blur.

Creating Edge Mask Selection

At this point create an edge mask from this selection to use on the image in the layers panel.  To do this, hold down the control key, then click on your duplicate channel to create an edge mask.

Edge mask selection. You should see lines in a running motion if you did this correctly.

Furthermore go back to the layer tab and go to Select > Inverse.  Then go to Filter > Sharpen > Unsharp Mask and apply your changes.  Click ok when happy.

Then go back to your channels tab and select all RGB channels.  Finally, deselect your copied channel.


Image after using edge masking. The edges have improved clarity.


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