Links 191-192

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Not so many links this time, I forgot to take notes…..

There was a meeting of GIMP guys at the LGM 2013 and Michael Schumacher took some notes. I like especially the part about getting good knowledge about GIMP out.

Pat David published some time ago a method to average images with ImageMagik. I stole one of his new results to illustrate this posting. A bit creepy, but you should have a look at his Playboy centerfold collection!

Really dry, with a blue suit and tie – but gooood! IBM has a nice introduction to Scribus, “the” Free and Open Source Desktop Publishing Program.

Not sure which Creative Commons License to choose? Petapixel has a graphic guide.

Rosie Hardy is a professional photographer and uses GIMP. Libre Graphics World shows some of her dreamy self portraits. She sells tutorial DVDs, BTW…….

This exhibition in Berlin sounds interesting, It’s not Nikon, but I’ll have a look.

And a new camera design, stolen from the bugs. (Thanks, Bob!)

 

 

 

Episode 191: PNG or JPG – The Big Fight

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This is a PNG in JPG lookDownload the Video! (26:07 49.7MB)

In the last Episode I looked under the hood of JP(E)G and PNG. This time it gets a bit more practical – which is better for what?

I tackle two examples from the GIMP Magazine web site and test, if they would be better saved as JPG or PNG. The Plugin “Save for Web” is really usefull for this task.(The image for this blog entry is a PNG by the way, showing JPG compression artifacts. As a JPG it would be five times the size. )

I “developed” a method for comparing two layers – just set the top layer mode to “difference”, make a new layer from visible and check that with the threshold tool for pixels, that are not completely black. After locating the problematic zones in an image with this tool, one can decide what settings are “good enough”.

Conclusion: It depends. It depends on the file, your use case, your level of “good enough” and your compassion for people on a mobile device in EDGE-Hell.

The show starts with a little extension of the last show, Pascal mentioned some options for saving a JPG file that I had overlooked.

The TOC

00:00:00 Start of video
00:01:00 Progressive mode in JPEG
00:04:09 Progressive mode is not fully supported by browsers
00:04:23 Optimized mode
00:05:56 Baseline?
00:06:17 The quality setting
00:07:09 GIMPMagazine and MTG header image – PNG or JPG?
00:09:23 Checking for quality loss in JPG
00:10:03 Comparing two layers with difference mode
00:10:48 Using the histogram for analysis of the amount of difference
00:11:25 Locating the differences
00:13:50 Trying 85, 75 and 90 as quality settings
00:16:13 When in doubt, compare different settings
00:16:36 Save your work as XCF.GZ
00:17:12 Second example – a drawing
00:19:56 Conclusion
00:23:19 Stay at 4:4:4 for subsampling with photos
00:25:16 Final words of wisdom
00:26:07 End of video

Creative Commons License
Meet the GIMP Video Podcast by Rolf Steinort is licensed under a Creative Commons Attribution 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.

Links 190-191

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The links for the gap between #190 and #191. I accept suggestions under info@meetthegimp.org. Even blatant plugging of your own stuff, if I like it. ;-)

The competition isn’t sleeping. And the sound will get better soon! Short and on the point – exactly where I suck. ;-)

A link to a German site (from Bremen! :-) ) with more quick tutorials. Get more Drama into shots with sky in them in 3 minutes.

Monitors for Photography – A Primer from On Taking Pictures.

An academic paper about Noise, Dynamic Range and Bit Depth in Digital SLRs. Looks interesting and is here also as a bookmark for me.

Darktable, the RAW converter and management program, has released a new version, 1.2. Cool stuff about camera specific noise and much much more! And they seem to get masks …..

Do you have a scanner, paper documents to process and run Linux? Then Konrad Voelkel has something for you: “After having bought a new flatbed scanner, I re-investigated how to scan and OCR pdfs, how to produce DJVU files that are incredibly small and how to get metadata right. It turns out what I really ever wanted was to create PDF/A compliant documents (I just didn’t know what PDF/A was before). But let me explain the details after presenting you the quick solution. At the end, I have a shell script that scans directly to PDF/A.”

The Rule Of Thirds on Steroids – Alfred Eisenstaed’s compositional system in an analysis of some of his images and a Degas painting. I am not sure if this is over-analysed or not, but it’s an interesting read.

My income is in the top 1%! Where are you on the Global Rich List?

Not a lake. Look at the “beach” on the left side.

What are we taking photos of? A survey of questionable statistical value but from an interesting site for teachers. Perhaps Germans include more under “random stuff” than other people…..

GIMP is now a Professional Photo Editing Software, available in a bundle with Blender and much more for only GBP 2.89 or US $4.37. Whow. Or better not, it’s free on other sites.

Episode 190: JPEG and PNG, what’s in it?

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190Download the Video! (36:10 68.8MB)

Download the Companion File! (4.6MB)

The last episode was for absolute beginners, this one is for Geeks. I try to explain (and understand on the way) how images are stored in PNG and JPEG files. PNG (pronounced “PING”) does this lossless, the image can be retrieved in the same quality as the original. PNG works wonders with graphics with a lot of lines and clear colour areas, comics and logos for example, but it creates monster files out of photos and similar images. JPEG looses details, aquires artefacts and generally mangles the image. But it has so beautifully small files and the losses are in most cases invisible – except in the area where PNG is good. So both have their niche to live in.

How is this done? I try to explain this without the math, using analogies, plaing with GIMP to reenact some stages and reducing the complexity a lot. If you want to know the exact facts, read up in Wikipedia, which was also my source of information, or look for other sources. I hope that I never crossed the border between simplification and telling wrong stuff – but I am really not sure. The math is really over my head, last time I had to tackle such a level a Pentax ME Super was still a new camera model. I am happy about any comments that improve my understanding – and all other comments too.

The TOC

00:00:00 Intro
00:02:22 Basics about digital images – pixel, RGB
00:05:25 Storing the colour values in the computer
00:06:24 Palettes for reducing the image size
00:06:50 Run length encoding as simple compression method
00:07:20 PNG, JPG and a WARNING
00:08:44 The PNG format
00:10:12 HexDump and structure of a PNG image
00:13:32 Compression in PNG
00:15:15 PNG is suitable for …
00:16:26 JPG analysed – file structure
00:18:13 First stage: Change the colour model to YCbCr
00:18:54 Decomposing an image to YCbCr in GIMP
00:20:32 Reduce the colours
00:22:20 Testing the concept with GIMP
00:26:17 Splicing into blocks and DCT
00:28:41 quantization
00:29:53 Summary
00:31:20 Testing the compression
00:35:19 Final words
00:36:10 End of video

Creative Commons License
Meet the GIMP Video Podcast by Rolf Steinort is licensed under a Creative Commons Attribution 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.

Links 189-190

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Here are the links for this Tuesday – a bit late, I managed to set the timer the wrong way…..

[UPDATE] I forgot one important link: A new version of G’MIC, numbered 1.5.5.1, has been released. It is really impressive. And David Tschumperlé’s car broke down and leaves him in a bad financial situation. David is the guy behind G’MIC, you know what to do with his donation buttons, don’t you? ;-)

Patrick David has a close look at skin faults. With Blue Light. And provides even a script for that. After reading that you know why RED light is more romantic…..

Do you remember LightZone? A really good program for Linux and MacOS, but proprietary code? No costs but threatening to charge in the future? It is now Free Software! Check it out – I want some opinions if I should go into it!

GIMPHELP.ORG has a script collection that has all compatibility problems with 2.8/2.9 ironed out. And more stuff.

Lens Fun is a library for correcting Lens Errors in digital images. And there is a plugin for GIMP to correct lens distortions using that plugin.

Setting up the Wacom Tablets in Gnome – I have to confess I just found that…..

Shotwell got way better RAW files magagement and a very special changelog entry.

The Bayer Filter is the usual way to get colour into the colour blind sensor and eat a ot of light on the way.. Now Panasonic has something new and brighter, Physics at it’s best. Let’s hope that they do better than the Foveon Sensor.

No DSLR, variable weather, playground and patient little blonde girl at hand for test shots? Try the camera simulator.

Nikon has a new firmware out for my camera! :-)

“The world’s best interview show about photography and all things creative.” His own words. But I like it very much!

Up to next Tuesday with an epic battle between JPG and PNG

GIMP Team gives in to constant nagging!

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mtc-logoAs the usually well informed Steve Czajka from the GIMP Magazine reports in a special issue, the GIMP Team has started to rebrand the project. The name GIMP wasn’t professional sounding enough to reach the self defined goal of building a program that fulfills the demands of graphic professionals.

The GIMP Magazine has already changed it’s design. I will follow when I have secured the new domain names, implemented the name server changes and updated the web server for the former GIMP Magazine and Meet the ???????.

They could have announced that a bit earlier…..

Episode 189: Currywurst for Beginners

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189Download the Video! (53:45 107MB)

Download the Companion File! (19.9MB)

This is an episode completely in “Beginners Level”, some of you have asked for such a thing. I go through the editing of an image and cover a lot of topics. Nothing really in depth, but you should be able to work your way through other material after viewing this one.

I start with a short tour through the user interface of GIMP, you find more about that in the GIMP documentation and other places. In between there is a bit about saving vs. exporting an image – without the nasty and pointless discussion.

The image itself has to be rotated a bit, cropped, treated with a bit of curves, burned, and dodged, given more omphh with a layer in overlay mode that of course has to be modified with a layer mask.  Finally the image will be scaled down, sharpened and exported as a JPEG while the original XCF file is conserved. Quite a tour – so I needed nearly an hour.

(I’ll update the links here later.)

The TOC

00:00:00 Intro
00:00:56 Comments about the GAP problems
00:01:43 This episode is for beginners
00:02:58 Currywurst and Friedrichshain
00:04:18 The user interface – a short tour
00:04:35 The window header and saving into XCF
00:05:30 Exporting an image as JPG or PNG
00:06:50 Fullscreen and single window mode
00:07:20 Menues, Toolbox, Docks, Tabs
00:09:23 The image area with the canvas, rulers, sliders and buttons
00:10:20 Moving around in the image and zooming
00:12:00 Single window mode vs. multi window mode
00:13:01 TAB to switch the Toolbox and Docks on and off
00:13:32 The image – back story
00:15:30 What has to be done – making a plan
00:16:40 Rotate the image to straighten it
00:19:17 Cropping to a 3:2 aspect ratio
00:19:57 Inside Out Cropping
00:22:50 Make a backup layer
00:23:20 Curves Tool for contrast changes
00:27:30 Burning and Dodging with a layer in Soft Light Mode for local brightness changes
00:30:50 An extra layer for notes
00:33:30 Burning and Dodging
00:38:00 The Smudge Tool
00:41:27 Increasing contrast with a layer copy in Soft Light Mode
00:43:30 Adding a layer mask to apply the effect selectively
00:45:50 Softening the layer mask with a Gaussian Blur
00:47:45 Saving the image
00:48:03 Reducing the size for the Web
00:49:30 Sharpening
00:51:38 Exporting to JPEG
00:53:45 End of video

Creative Commons License
Meet the GIMP Video Podcast by Rolf Steinort is licensed under a Creative Commons Attribution 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.

Links: 188-189

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Just to fill the week between the episodes – some links for you.

  • Find images under Creative Commons licenses with matching colours at TinEye.
  • Creative Commons? Yes, they need some money. ;-)
  • German photographer/digital artist/photoshop trainer Calvin Hollywood has a rather unique style to his photography. It’s a sort of edgy, gritty, hyper-realistic result, almost a blend between illustration and photography. Find out how to do something similar im GIMP at Pat David’s blog.
  • Learn all about the power of Curves at Cambridge in Colour. It’s about “The Other Program” but true for GIMP too.
  • Scripts and scripting for GIMP is covered by gimpscripts.com. Some contributors sound vaguely familiar. ;-)
  • GIMP team revitalizes astrophotography tools. Alexandre Prokoudine at Libre Graphics World reports and adds a bit of documentation. See also Episode 156 about this topic.
  • All the Math behind panoramas and more from the MAA.

Episode 188: The Book

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188Download the Video! (37:10 74.1MB)

Download the Companion File! (0.3MB)

This episode is about using GAP, the GIMP Animation Package, and “The Book of GIMP”. I walk through one of the tutorials of the book and create a multi layered animation that will be used in a cleaned up form for these videos. I can not praise the book enough, you can read more in a former blog post. GAP showed some flaws, but this may be the problem of the Debian package that I used.

“The Book of GIMP” has also a reference part. I compare that to the official GIMP documentation while looking for information about the Convolution Matrix.

Before all that I tell you about a GIMP plugin for exporting a layer as a PDF file and I defend my new camera – 36 Megapixels may not be too much, they only show the limits of the lenses…..   Cameras with smaller sensor sizes of course hit a barrier with more and more MP.

The next episode will have animated lower thirds and a proper automatically generated title screen. ;-)

The TOC

00:00:00 Intro
00:00:14 GIMP Magazine #3
00:01:20 Plugin for PDF export of layers
00:01:48 Are 36 Megapixel too much? (Nikon D800)
00:04:08 Where are 6 Megapixels enough? Sensor sizes
00:05:40 The Book of GIMP review
00:07:12 Testing the animation chapter
00:08:27 GAP – Moving Along a Path
00:10:12 New image from template and transparent background
00:11:50 Planning the animation
00:12:16 Building a dummy
00:13:40 Selecting the border of a selection
00:15:55 Make a new image out of a layer
00:17:10 GAP: Duplicate a layer 20 times
00:18:00 GAP: Move Path Tool
00:28:50 GAP: VCR Playback
00:29:30 GAP: Exporting an animation
00:31:40 The Manual part of “The Book of GIMP”
00:32:00 “The Convolution Matrix” compared with docs.gimp.org
00:35:30 Help to improve the documentation!
00:36:00 The printed book and the final verdict

Creative Commons License
Meet the GIMP Video Podcast by Rolf Steinort is licensed under a Creative Commons Attribution 3.0 Unported License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.