by Medley on Tue Feb 13, 2007 9:14 pm
There are as many sharpening techniques as there are images, and with good reason- sharpening should always be tuned to the image being sharpened.
That said, here is a techmique which works well in general, and one I use when batch-processing photos:
1)Convert the image to Lab color: Image>Mode>Lab Color
2) Copy the background layer: Cmd-J (PC: Ctrl-J)
3) Go to the channels palette, and Cmd-click (PC: Ctrl-click) on the Lightness channel. This creates a selection based on lightness.
4) Invert the selection: Cmd-Shift-I (PC: Ctrl-Shift-I), and hide it: Cmd-H (PC:Ctrl-H)
5) Go to Filter>Sharpen>Unsharp Mask and apply the following settings: Amount 500%, Radius 1.0 pixels, Threshold 2 pixels.
Note: depending on the image resolution, 500% may be too much. I never use less than about 300% however.
6) Go to Filter>Sharpen>Unsharp Mask and apply these settings:
Amount 50% Radius 20 pixels Threshold 2 pixels.
Note: If 500% was too much in the first application, 50% is probably too much here. 35-40% may work better.
7) Convert back to RGB: Image>Mode>RGB
You can now toggle the top layer on and off to see the difference. You could also adjust the opacity of the top layer to soften the sharpening effect.
Hope this helps.
-Medley.