I am back!

Life threw some interesting stuff in my direction – mostly positive – that consumed a lot of my time and attention. But now I have some capacity to come back to this project.

It will take some time for the next video. First I have to rebuild my production pipeline – and that is an interestimg task too. My favorite video editor Cinelerra crashes all the time – I have to learn Blender for editing. And then there is the screen recording with a lot of newoptions and some nice new ways to encode video…..

218.22.2X.X in Hefei, China – Please don’t scrape the site!

Meet the GIMP and the GimpMagazine have been offline for hours today, because someone needed to download all the content in parallel. I have no idea if this is flattering or an attack. I have blocked the IP and will re-open it after I got a mail from you

This was simply too much load for the machine.

rtm_692051918086

Edit: Now the machine should be able to keep up, I limited the memory consumption of Apache. It will be slow, but will stay up.

The next video is in the works, I can start editing tomorrow after the grades meetings are over. Lots of stuff happening here, more in the show.

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

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.

Good Book about Blender coming up – get 40% off until Feb 28!

The book is a great introduction into the creation of static Blender scenes. Motion with armatures and animation is not covered. But you can get that online in a lot of places.

This book is unique in its inclusion of the creative process. It follows three projects (a Mayan temple, a bat winged humanoid and the robotic spider from the title) from first pencil sketch to the final rendering. Each chapter covers one stage of the process and does that for each of the three projects. It even contains a good introduction into GIMP for creating textures. It shows that the author Ben Simonds is not a developer but a professional 3D artist.

I have (speed) read through my review copy of the PDF and am waiting for my paper copy to start to play a bit with Blender again.

With a code you can get 40% off until Feb 28. That would be around $30 for the print copy and the e-Books. Not bad.

A review of this book will be in Episode 187 on Feb 26. If you view that episode before the 28th you can decide after looking over my shoulder into the PDF.

(So much NoStarch titles here? Well, Jessica from their marketing has my mail address and offers to throw books at me quite often. And if they fit into the wide scope of Meet the GIMP, I’ll accept. Except for the free book I get nothing for the review – and I have no obligations to like them or tell only good stuff. If other publishers want to throw books in my direction to break the NoStarch dominace, just drop a mail at info@meetthegimp.org 😉 )

Episode 185: The 52.02 €rror – Printing with Profiles

Download the Video! (36:50 73.4MB)
Download the companion file with my printer profiles! (3.9MB)

I gave myself a real photo printer for the 5th anniversary of “Meet the GIMP!” and have now my work-flow ready to print in the “right” colors. One reason I shied away from printing for years were the costs. Original Printer Ink is one of the most costly fluids that are traded commercially (1544.54€/l (1) is not the highest price you can pay) and good paper is expensive. But now I have found a combination of a good printer, which is subsidized by small and expensive ink tanks and a good second party ink for 1/6 of the price. The ink is pigment based and so doesn’t bleach out in the light so fast as dye inks. Added to that two good but cheap papers for making beginners mistakes.

Of course the colors are off when I print with the usual TurboPrint driver. TurboPrint knows neither ink nor papers. So I needed two printer profiles – one of them was already payed for with the ink starter set. Well, I had to buy two more profiles because I had made a big mistake while printing the test sheets. Take care to switch off all color correction while printing calibration charts.

With the right ICC profiles GIMP can give you a Soft Proof of the image that is going to be printed. The look of the printed image is simulated on the screen and you can adapt the image to get your best result.
All you need to know (and much more) about calibration and the different “intents” is at Cambridge in Colour and at the Idea Machine.

(1) It’s even worse than I said in the video. The ink cartridge holds 11ml and costs 16.99€ Epson list price. That’s 1544.54 per liter. farbenwerk C7 runs up to 275€/l in the set and 230€/l for the ink only. Quite a difference.

The TOC

00:20 Gimp Magazine had a great start
01:10 New printer
03:00 Replacement ink by farbenwerk.com
03:50 Pigment ink vs. dye ink
05:50 Arguments for refillable inks
06:30 Filling of cartridges
09:20 Paper from Monochrom.de
11:20 Paper color changes the image
11:50 How printing works
16:00 Printer profiling explained
17:00 Profiling done
21:30 Getting the profile into TurboPrint
23:50 Soft proofing in GIMP
24:30 Out of gamut colors
25:40 Display filter for soft proof
26:30 Printing a real image with profile and soft proof
27:30 Adapting to printable colors with curves
30:10 Difference between LCD and paper / display intent
31:00 Printing in TurboPrint
34:15 6 colors – all black (Carbon ink for monochrome images)

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

Episode 183: Dynamics!

Download the Video! (20:20 40.5MB)
In the last episode was a short segment about the brush dynamics in Ramon Miranda’s GIMP Paint Studio. I wanted to read up a bit about this, but the GIMP documentation hasn’t held step with the development here.

So this video shows my exploration of the brush dynamics control. The possibilities are limitless, it seems.

The show starts with another GIMP theme by samj and a big misunderstanding. You can find everything about it at Gimp Chat.

The TOC

00:30 A dumb thing to do
01:10 The license for all Meet the GIMP stuff
03:00 Another GIMP theme by samj
03:50 Mice, Trackballs and Tablets
04:20 Absolute positioning
05:00 Modes of a tablet – pressure
06:10 … velocity, direction, tilt
08:00 … random
08:20 … fade
09:15 You started tablet training as a toddler
09:50 Setting up a tablet in GIMP
11:00 The pressure curve
12:45 Tablet sizes
13:30 Mapping matrix – controlable features of a brush
16:40 Dynamic curves control
18:40 A special non repetitive brush

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

Monsters!

A long time ago we had a tutorial by Bert about autostereoscopic images. Now I got pointed to these beauties. All hand drawn and very impressive.

The class trip was great, the kids behaved quite reasonably for being around 14 and we had enough wine for the night watch. 😉 The weather was less good as announced while we had indoor activities but turned to sunshine the moment we started our bike ride and other outdoor sports. I found out that I am not that bad as an archer.

Episode 177: Take 2 and GIMP!

Download the Video! (22:22 44.6MB)
Download the companion file from Episode 176!
Nachbarnebenan continues his tutorial from the last episode. He isolated his model from the a bit to vivid background by making two images from his RAW file. One is crisp and colourful – best for the model. The other one is soft and a bit dull – this tones the background down.
In this episode he combines them to one image with a layer mask.

Did you know that there is a filter in GIMP to emulate the look of an image for colour blind people? Nachbarnebenan shows how to use it. It’s no so important for photography – but think of all the graphics work done with GIMP. By using this filter you can make a difference in accessibility

If you want to get into programming plugins for GIMP in Python – here is the link to this great HD video from Gimpusers.com.

And for the next episode you’ll need a Trench coat and dark glasses – we’ll enter the Stasi headquaters at night.

Sorry, no TOC up to now, but at around 15:30 is the great segment about GIMP and colour blindness.

Creative Commons License
Meet the GIMP Video Podcast by Rolf Steinort and Philippe Demartin is licensed under aCreative Commons Attribution-Share Alike 3.0 Germany License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.

Grading Season

I have been very silent in mail, forum and video lately – it’s simply the grading season. Still standing in waist high piles of numbers, spread sheets and student output. Next week the worst is over.

EDIT Jan 23 – Well, one can dream…. I had a corrupt grade table to fight and some minor trouble with printers and paper. And then my PC power supply went dead Friday night. One Capacitor had a nice bulge on it’s head. Bought a new one, it stopped working after an hour and then of course the store was closed. Now I have a new one which seems to work fine. Tomorrow is completely filled up with work but on Wednesday I have a free afternoon for making a show.