Gimp "Smart" Sharpening, Redux

http://www.gimpguru.org has a write up "Smart" Sharpening, Redux this is a nice article on sharpening with GIMP.

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In my older tutorial Smart Sharpening with The GIMP I describe several techniques for selective sharpening of digital images to avoid exacerbating sensor noise and film grain. This technique does two "smart" things to avoid sharpening noise:

1. sharpens only the luminosity data in the image, thus avoiding shifts to the hue and saturation components (which affect color), and
2. targets only the edges in the image, avoiding large smooth areas that may contain noise.

In this tutorial I describe a variation on the technique that uses layers, which confers the following advantages over the original method:

* it does not modify the original image, which remains unsullied on its own layer;
* it is less laborious, with fewer steps;
* it avoids a costly mode change to HSV and back to RGB for unsharpened areas (see older tutorial for an explanation of this);
* it reserves sharpening for the final step, which allows better experimentation with sharpening parameters; and
* it provides an additional level of fine-tuning over the final result (see Tips).

All in all it is a far superior method to the old. Nevertheless, if you haven't read the original tutorial, you may wish to do so now.
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This is a great read for those of you using GIMP.