Posts Tagged ‘raw’
February 22nd, 2010 by Rolf
Download the Video! (37.8 MB, 19:53)
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(Mobile version tomorrow)
The German word “Terrorie” was coined by a kid in a Physics lesson of my late colleague Helmut Mohr in Hamburg. It is what it sounds like – and today’s video is full of it. No GIMP, no images, only the blackboard and me talking. Please consider this as a WARNING. 
We had a lively discussion in the forum about the theory behind making images, circling around the term “dynamic range”. There is a big difference between light and dark parts of our world, often more that a camera can catch. And nearly always more than fits onto paper or a computer screen.
The process of squeezing this big range into the small output range is called Post Processing. Either you do it via RAW anf GIMP – or the smart chip in your camera does it while saving your iage as JPEG. What I forgot to say – if you do it, you can redo it. The RAW file still exists. If the chip does it, the RAW file is discarded and you are stuck with the version of the image made by the chip.
I got a lot of information about this subject from a wonderful paper by Karl Lang at Adobe(R). Worth to download and read, even if you decide to skip the video this week.
The TOC
02:04 Orders of Magnitude
04:00 How much light is in a scene? (Dynamic range ramp up)
06:00 There is no black and white
06:30 Dynamic range of a scene
06:50 Dynamic range of LCD and prints
08:50 Dynamic range of the camera
09:50 Exposure = slide the dynamic range
11:05 Post processing by the camera
12:15 RAW -> GIMP -> print
13:00 Slides and egatives in analog photography
15:05 A source at Adobe(R)
15:15 8 Bits – a problem (sometimes)
17:10 Why is it possible to make images? Because our eyes are no camera and our brain no computer.
“Meet the GIMP” by Rolf Steinort is licensed under a Creative Commons Attribution-No Derivative Works 3.0 Germany License.
Permissions beyond the scope of this license may be available at http://meetthegimp.org.
Tags: 8 Bit, dynamic range, post processing, raw
Posted in Gimp video tutorial, Photography technical basics | 14 Comments »
August 6th, 2009 by Rolf
Download the Video! (74.4 MB, 39:09)
Download the Video for iPods etc (40.0 MB, 39:09)
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Download the Companion File! (24.5 MB)
You can win a book in our two contests – the exact rules will be published in the next posting.
I continue to work on my project “Access Control”. My target is a photo book by blurb.com. They accept PDF files for printing – which is important for me because most of the book making software of the printers doesn’t work on Linux. Of course there is an Open Source program for making a PDF – Scribus. It is available for all OS, even OS/2. I’ll tell you about my experience in one of the next episodes.
A bit of Magic is shown by Philippe – and I have confess that I used an old version of his script. You’ll see better ones next time.
There are a lot of photobooks to look at for inspiration at SOFOBOMO.
Then I start to edit an image. The JPEG image is a bit overblown in the highlights and I have to go back to the RAW file. Cropping turns out to be difficult and the image needs a bit of a contrast boost in some parts.
The final steps – sharpening and deciding about a vignette will be made when the layout of the book is clear. For sharpening one needs to kknow the output resolution and size – and I will have to scale the image to 300 DPI before putting it into the book. The vignette depends on the background of the page.
The TOC
00:20 The Book Challenge
05:20 A Photo Book as the target for “Access Control”
07:50 Scribus for making PDF files
10:00 Photobooks to look at
10:35 Editing an image for the book
11:15 Blown out pixelss
11:45 RAW to the rescue with UFRaw
16:28 Comparing JPEG and UFRaw output
18:50 Correcting a colour cast in UFRaw
20:45 Straightening the image
23:00 Cropping the image
26:50 Improving contrast with a layer in overlay mode and a mask
33:20 Crooping more
35:00 What’s left to do
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.
Tags: Access Control, enhance contrast, overlay mode, PDF, raw, Scribus, UFRaw
Posted in Gimp | 20 Comments »
November 25th, 2008 by Rolf
I got a mail from Pascal de Bruijn, the man behind the p-code blog. He knows a lot about colour management, RAW processing and so on. He had seen episode 11 and pointed me to some errors and stuff that is new in UFRaw. So I read his mail and had a look.
This is really a fast forward through the program, nothing really in depth. It can be a guide for experimenting. If you know not much about RAW processing, have a look at episode 11. It covers some basics about the technology behind it.
I used the UFRaw version compiled by Pascal. You can find it for Ubuntu on his site – other OS have to look around. Start with the UFRaw home page.
I’ll have an eye surgery tomorrow (lens replacement) and had not much time to prepare this episode. TOC and more will follow. And I’ll be off screen for some days until I am allowed to read again.
The TOC
0:00 Intro
0:26 Statistics
1:50 Pascal’s e-mail blog.pcode.nl
4:16 – Fire up UFRaw!
4:30 – Color matrix vs. Color profile
5:57 — Working Color Space Profile
6:33 — Rendering Intent Option
8:50 – Details Restauration & Highlight Clippings
10:13 – Import base curves from .NCV
10:26 – Auto black point correction works perfectly!
11:13 – New features in new version of UFRaw
11:36 – LensFun
14:00 – Fix cromatic aberration
15:57 – Optical Vignetting
16:23 – Lens distortion – Panotools
17:16 – Lens geometry
19:18 Outro
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: raw, raw conversion, raw processing, UFRaw
Posted in Gimp, Gimp video tutorial, Other OS software | 29 Comments »
April 29th, 2008 by Rolf
Brand new tech- nology meets stuff from the Stone Age, ehm… the 70′s.
Rawstudio’s 1.0 release sits on the lab bench for a test run. I am impressed by the workflow and the overall appear- ance. The output in the video has some noise in it, but that was my fault.
I had my camera set up to store a RAW and a JPEG image and have put both files and the camera profile into the companion file to this episode. Now you can try to get a better image out of the RAW file than the processor of a Nikon D200.
In a lot of discussions and tutorials you read the term “lith” or “lith film”. One is running in the meetthegimp.org photogroup at 23.hq. I found an old box with real lith film and take you back some decades while describing how I have worked with these sheets of plastic.
Then I try to rebuild one of the effects that were done with lith film in GIMP. I just emulate the effect, but I am working on a process to really simulate the process done with film. You can find the file to this part of the podcast also in the companion file.
How did you like the concept of these two last shows? Not one monolithic block but several shorter segments? I want to offer a mix of different topics in each episode, covering different levels of experience and different interests. I have put up a poll for you to vote on the side bar. If you want to give me more input than just a click, write to info@meetthegimp.org or post a comment here in the blog.
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: converter, lith, lith film, raw, Raw converter, Rawstudio
Posted in Gimp, Gimp video tutorial | 14 Comments »
October 29th, 2007 by Rolf
Marcin (Martii) pointed me to this RAW conversion program. It does run under Linux and Windows XP/2000. No mention of Vista or Mac.
The screen shots look nice, but I haven’t tried it yet. Shall I cover this program in a show? It doesn’t seem to be open source, but free to download. Where shall I draw the line?
HINT: There is a Donation button on his site. Use it, if you like the software.
Tags: raw, raw conversion
Posted in Gimp | 11 Comments »
October 17th, 2007 by Rolf
I shot some autumn scenes with a Lensbaby in a very mixed light condition. And I haven’t checked the histogram after this shot. It is the only one with the focus right on spot and a dreamy flair. The leaf in the center was overexposed in the JPG image – blown out highlights ruined the image.
This is the final image – not the one with the blown out highlights….
But I had shot in JPG and NEF (Nikon’s RAW) – so I used UFRaw to produce a TIFF file with the right exposure of the leaf and blended it into the image with a layer mask. This is basically the way (pseudo-) HDR works. Take different parts of the image from differntly exposed photographs.
A slight correction with the hue/saturation tool was necessary to adjust the colours. Cropping was done twice – a mistake made a correction necessary. So I covered some advanced options in cropping.
I promised some links:
Don’t forget to make a triptych and post it in the photogroup. I’ll draw a winner for the one year 23Plus membership sponsored by 23 in show 16. So you have still time to Oct. 18 to submit an entry. The pictures there are already worth to be looked at.
Get the files used!
The files from this episode.
The TOC
00:23 Welcome
00:34 Triptych challenge
02:55 More on liquid rescale
05:36 Red Hat Magazine
07:04 The Lensbaby source image
09:47 Raw conversion using UFRaw
14:30 Open in Gimp
15:00 Add TIFF as a new layer
16:00 Aligning the layers
18:18 Add a layer mask
21:45 Adjust the hue-saturation
25:46 Crop the image
28:40 Reduce the file size by cropping the top layer
30:00 Remove a distraction using the clone tool
34:48 Resize for web
37:40 Sharpening
42:23 the End
TOC made by paynekj
Contact me!
You can leave your comments on this blog or write me a mail.
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: blown out highlights, crop, hdr, hue, layer mask, Lensbaby, raw, UFRaw
Posted in Gimp, Gimp video tutorial | 3 Comments »
September 24th, 2007 by Rolf
I try to explain the stuff that influences the quality of your images. File formats, compression, sensor size. Each solution has pro and cons – you have to decide what you need and want.
All the file formats are explained at Wikipedia.
Some stuff about sensor sizes. Quite old but still true.
And this are some of the guys with the big sensors.
The TOC
00:23 Welcome
01:05 Digital camera sensor size
06:56 Colour Depth
11:14 Compression
13:29 File Formats
14:18 Which file format to use
21:07 The End
TOC made by paynekj
Get the files used!
The files from this episode. Beware!This are 55 MB!
Contact me!
You can leave your comments on this blog, write me a mail or go to the Tips from the Top Floor Forum.
This work is licensed under a
Creative Commons Attribution-Share Alike 2.0 Germany License.
Tags: file formats, image quality, raw
Posted in Gimp, Gimp video tutorial | 10 Comments »
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