'Sharpening with 'High-Pass Filter' ..... continued

Clive R. Haynes FRPS

Set High Pass radius to between 4 and 8 - this increases the 'fringe' effect
(Above: the High Pass filter dialogue box and effect on section of image)
To provide a reference, the screen-grab above illustrates the effect of colour fringing if the image is not desaturated. Notice the fringing effect at the upper edge of the eyelid in particular. It's difficult to ascertain from the screen-grab above but without desaturation the colour of the image tends to be over-enhanced. Desaturation is recommended.
To illustrate the effects of using three most usual Blend Modes for High-Pass Sharpening, the images that follow show 'Soft Light', 'Overlay' and 'Hard Light' modes. The series begins with the unsharpened original.
The examples are all at 500% on-screen magnification as an aid to comparison. The images are also of necessity quite large to better show detail, therefore load-times may longer than usual.
Above: Unsharpened original  at 500% on-screen magnification
Above: 'Soft Light' Blend Mode at  500% on-screen magnification
Above: 'Overlay' Blend Mode at  500% on-screen magnification
Above 'Hard Light' Blend Mode at  500% on-screen magnification

A further refinement is the application of a 'Layer Mask' to selectively sharpen parts of the image.

For more information about this, click on the 'Selective Sharpening' link below.


Related Topics
Selective Sharpening
Sharpening Edges Gently
Sharpening in 'Luminosity'
Sharpening Texture with 'Emboss'
Know-How Contents
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