Every digital image needs sharpening. But sharpening increases the noise in the image. In this episode I show a way to sharpen only the areas that need to be sharpened – the edges between different colours or levels of brightness. All the other parts of the image are left alone and so the noise stays down.
Sharpening should always be the very last thing you do with your image.
Chris Marquard explained sharpening in Photoshop Corner No. 4 in his Tips from the Top Floor podcast.
I got the described method from the Gimp tutorial page.
Wikipedia describes the underlying process in this article about the unsharp mask. The links at the bottom of the page are very informative.
Meet the GIMP! is now listed in iTunes and Podcast Alley. If you like the show please let the people there know. 
You can leave your comments on this blog, write me a or go to the Tips from the Top Floor Forum.
The TOC
00:22 Welcome
01:00 The original image
01:25 Why we want to selectively sharpen
02:38 Copy the layer and add a layer mask
04:00 Edge-Detect on the layer mask
06:40 Blur the layer mask
07:12 Increase contrast using curves
08:34 Sharpen the image
10:25 Fine tuning
14:35 How sharpening works
15:49 tips from the top floor
18:26 The End
TOC made by paynekj
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: selective sharpening, sharpening
Please send me the image for this episode. I want to try it!
I am learning a lot, but I know I will learn even more when I review each episode later. My learning curve is SO high now. Experience tells me that the more I already know, the more I can absorb.
Thanks for your wonderful work.
Hey, just stumbled across your podcast and I just love it. I’ve been on the Linux platform for some months now and haven’t been missing anything accept Photoshop. You have wiped out the last reason for me to keep a Windows partition on my harddrive! Thanks!
Keep up the great work!
/Sebastian
I’ve been using portable Gimp from portableapps.org and think it would be useful if you could explain using UFRaw for pulling in RAW images. I use it currently, but understanding the dialogs is somewhat confusing.
@rmh1985: I put the images online at http://www.23hq.com/rstein/album/2336004
@Sebastian: Power to the Penguin!
@Matt: UFRaw is on my list – will be covered in a show soon.
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Hello,
there will be no effect, if my sharpend-layer is in the normal mode.
Only the overlay-mode will show the sharpen effect, but then some colors have much more saturation.
Whats wrong? Gimp 2.6.6
@josip – No idea, but I’ll be happy to have a look if you publish a link to your image or send it to me by mail.
You could start a thread in the forum by pasting your XCF file. I’d bet you will find a lot of help