Meet the GIMP #80: Hi Bert! (Ernie not included)

Posted in Graphics on April 30, 2009

Meet the GIMP #80: Hi Bert! (Ernie not included)

This show is two days late - lots of work and again some eye trouble. This time the other one - but it is working out.

Bert (Ray Adagio on the Forum) is the star of this episode. He has written some great scripts and enhanced others, the Zone Adjustment script for example. And now he has tackled rotation. You just have to mark two points on a vertical or horizontal line and click - the rotation starts. Ok, the tool from the toolbox has way more options, but usually you don’t need them.
Bert has also started a discussion about sharpening in different colour modes. Sharpeneing the “L” of LAB should be the best way, but this involves a lot of lossy math in 8 bit mode. Forget about it. But sharpening the “V” of HSV can be an alternative.

The animation in this post has a lot of artifacts due to the 256 colours of the GIF image. The real ones are better. All the example images are in the companion file of episode 79, not 78 as I said in the video. Only the one with selective sharpening is in the ZIP file for this episode.

I add a way to do a selective or high pass filtering in HSV. Perhaps in a script on a server near you in the future.

Sharpening is a topic that has to covered in later episodes. On can sharpen a colour channel (gree is best most of the time) or use different values for the USM (unsharp mask) algorithm. How that thing really works would be interesting too.

Information about the DOCMA Award 2009 can be found in the forum. I’ll update that tomorrow.


00:30 DOCMA Award Challenge
02:30 Subscribe and donate
04:20 Writing scripts
05:00 Rotation script
06:20 Install a script
08:00 Missing folders - no problem
08:45 Using the Rotation script
11:25 Sharpening in LAB?
12:30 HSV and LAB
14:45 Differences between RGB, HSV and LAB sharpening
20:40 Conclusion
21:15 Decompose
22:00 Unsharp mask
23:30 Adding a layer mask for selective sharpening
24:00 Edge detection
25:30 Temporary layer for controlling the effect
27:30 Recompose the image
29:00 Adding an image into a new layer
30:00 Conclusion - there are more ways….

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Tags: Design, GIMP, Meet the GIMP, Broadcasting, Screencasts, Script#, fake, sharpeing