Sharpening a Photo without increasing Noise Visibility in Photoshop CS5
This tutorial will teach you a method of sharpening an image without increasing the noise visibility. This tutorial will be completed in Photoshop CS5 but should be compatible in versions CS3 and higher. This tutorial will assume you understand the basics of Photoshop, if not refer to one of our beginning tutorials.
Step 1) Starting the tutorial
First you will need to find an appropriate image to work with. Once you have found one open it up in Photoshop so we can begin.
From here Go to Window > Channels. The first step is to look at the channels palette and determine which color channel will best represent the area we want to capture. To the right, shown from top to bottom, you can see the red, blue, and green channels for this image. It is obvious that the red channel contains the most information because it is the most light. Click on the red channel and drag it down to the new channel button to create a copy.
Step 2) Using the target channel to add some styling
We got the copy as you can see in the picture above. Once we have this, we are going to apply a filter to this newly copied layer.Go to Filter > Stylize > Glowing Edges with settings similar to below
We should now have an effect like this
Hold the Ctrl button and click the Red Copy thumbnail in the channels palette to load a selection of this channel.
Step 3) Apply the Sharpening
After we have the selection we can delete the copied channel. To do this click on the red copy channel and drag it down to the delete current channel button. Now that this is deleted we can do to the layers palette or Windows >Layers and press Ctrl + H to hide the selection temporarily. Now we can apply the sharpening filter. To do this go to Filter > Sharpen > Unsharp mask. We will use some suitable presets for the photo.
You can now see the result:
Step 4) Finishing the sharpening
Now, we have a selected area that is hidden, so press Ctrl + H to make it visible again. Now press Ctrl + J to duplicate the selected area into a new layer. Now apply Filter > Sharpen > Sharpen Edges
That is it for this tutorial. You have sharpened the photo without increasing any noise visibility. This technique will work for all photos as long as you understand color channels. As always the source files will be available for you to download and help you along the way.