Insufficient sharpness happens to be one of the most frequent defects photographers encounter. But correction filters allow you to solve this problem by making the image longer and sharper. The filters correcting sharpness let you increase it by increasing the color contrast of adjoining pixels. However, none of them can add missing details in the less vivid parts of the image - they just create the needed impression.
1. Sharpen
This filter increases the contrast of adjoining pixels.
Open the image and select Filter>Sharpen>Sharpen. The filter has no settings , so you'll get something like this:
2. Sharpen Edges
This filter increases the contrast of adjoining pixels, but only for contours, or edges. That means it applies itself only to the areas with initially maximal contrast.
To use it, open your image and select Filter>Sharpen>Sharpen Edges. This filter also has no settings, so you'll have something like this in the end:
3. Sharpen More
This filter's role is predictable from its name: it works very much the same as Sharpen, only to a greater extent. You get to it through Filter >Sharpen>Sharpen More. This filter also has no settings:
4. Smart Sharpen
This filter lets you set the sharpening algorithm. It also lets you control the amount of sharpening that occurs in shadows and highlights.
To go on sharpen, open the image and then select Filter>Sharpen>Smart Sharpen. There, you'll find the following settings:
Amount - Sets the amount of sharpening. A higher value increases the contrast between edge pixels, giving the appearance of greater sharpness ( I set it to 50%).
Radius - Determines the number of pixels surrounding the edge pixels affected by the sharpening. The greater the radius value, the wider the edge effects and the more obvious the sharpening ( I selected 1,5px).
Remove - Sets the sharpening algorithm used to sharpen the image. Gaussian Blur is the method used by the Unsharp Mask filter. Lens Blur detects the edges and detail in an image, and provides finer sharpening of detail and reduced sharpening halos. Motion Blur attempts to reduce the effects of blur due to camera or subject movement ( I selected Gaussian Blur).
Angle - Sets the direction of motion for the Motion Blur option of the Remove control (only for Motion Blur).
More Accurate - Processes the file longer for a more accurate removal of blurring (unchecked in my picture).
Advanced - Adjusts sharpening of dark and light areas using the Shadow and Highlight tabs ( I used basic).
Fade Amount - Adjusts the amount of sharpening in the highlights or shadows.
Tonal Width - Controls the range of tones in the shadows or highlights that are modified. Move the slider to the left or right to decrease or increase the Tonal Width value. Smaller values restrict the adjustments to only the darker regions for shadow correction and only the lighter regions for highlight correction.
Radius - Controls the size of the area around each pixel that is used to determine whether a pixel is in the shadows or highlights. Moving the slider to the left specifies a smaller area, and moving it to the right specifies a larger area.
So, here is what I got:
This filter finds pixels, which differ from the adjoining pixels to a level which exceeds a certain threshold level. The contrast of the adjoining pixels is increased upon a given value. As a result, the contrast is enhanced along the borders of different color areas.
Having opened the image, select Filter>Sharpen>Unsharp Mask. You'll see these settings:
Amount - controls the degree of contrast increase (I chose 8)
Radius - sets the radius of pixels processed by the filter (I selected 8)
Threshold - determines the difference between adjoining pixels, below which they will be regarded as a homogenous area, and thus won't be processed by the filter.
Here is my result:
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