Sharpening.
How to sharpen an image? A hard question to answer in any standard
way. For one it all depends on how soft the image is initially.
Also most images have some areas that are softer than others, so
a uniform amount of sharpening will not be ideal. Another factor
to consider is noise, which is the by-product of the sharpening
process and is something I want to avoid. So I only want to sharpen
the parts of the image that require it.
The first method
I will use is an Edge Sharpening technique. This is how it works.
1. Create a duplicate
layer of my background. And set Layer mode to Luminosity.
2. Select all of the
layer
Select > All (Ctrl
A)
3. Copy
Edit > Copy (Ctrl
C)
4. Select the channel
palette and press the ‘Create New Channel’ button which
is at the bottom of the palette, to the left of the ‘delete
bin’ icon. You will see the screen go black as you create
this new channel. Now paste your image into the channel.
Edit > Paste (Ctrl
V)
Now deselect the image
Select > Deselect
(Ctrl D)
5. Now I want to find
the edges. These are the only parts of the image I want to sharpen.
Filter > Stylize >
Find Edges
6. Now the edges might
not be quite as defined as I require so I am going to adjust the
levels of the image.
Image > Adjustments
> Levels (Ctrl L)
I am going to move the
left slider up to a value of 75. Remember that the black areas of
the image will be sharpened at 100% down to 0% in the white areas.
Click OK on your level box when you are happy. I tend to find that
a value of 75 works well.
7. Now I want to create
a selection from this Alpha channel that I can use for sharpening.
To do this press the circular icon at the bottom of the channel
palette. Now you will see a selection on your screen. I want to
invert this selection as I want to sharpen inside the selection,
not outside, as it is currently set. To do this I simply select
Select > Invert (Shift+Ctrl
I)
8. Now delete that Alpha
channel you have created by pressing the Bin icon, found at the
bottom right of the channel palette. The Alpha channel goes and
leaves you with a good selection on your image to apply sharpening
into. Now just apply some USM.
Filter > Sharpen >
Unsharp mask
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