Episode 198: Darktable revisited

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darktable is an open source photography workflow application and RAW developer. A virtual lighttable and darkroom for photographers. It manages your digital negatives in a database, lets you view them through a zoomable lighttable and enables you to develop raw images and enhance them.”

I cant say it better than this bit from their page.

I had tested darktable in 2010 and found it promising – but stayed with f-spot and later Shotwell. But now I’ll switch to darktable.

These 42 minutes are a rigorously cut down version of my nearly 2 hours long walk through darktable – I was distracted so much by the endless modules and possibilities that I forgot the time. This will not be my last darktable video, I’ll try to focus a bit more on usable stuff in them. 😉

You can find Pascal’s videos at pcode.nl, you have to search a bit for them.

And here is a collection of darktable videos, recommended by our Bert (rayadagio).

The TOC

00:00:00 Start and book savings announcment
00:02:32 Darktable startup
00:03:50 Importing images and grouping them
00:06:10 Copying and moving images
00:09:00 XMP files
00:10:30 Tagging
00:11:35 Geotagging
00:15:00 Rating and marking images on the Zoomable lighttable
00:16:20 The manual
00:18:30 The darkroom
00:21:00 The interactive histogram
00:21:40 Undo with the history stack
00:22:20 Lots of modules
00:25:40 Cropping and rotating
00:27:00 Zooming in the darkroom
00:29:30 Non destructive editing
00:30:20 Levels and curves
00:32:30 Stacking curves (and other modules)
00:33:20 Color correction
00:34:20 Monochrome conversion with color filters
00:35:30 Correction lens errors and lots more modules
00:39:00 Exporting the image
00:42:00 EOF

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Episode 160: Photivo

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Let’s quote the website:

About Photivo

Photivo is a free and open source (GPL3) photo processor. It handles your RAW files as well as your bitmap files in a non-destructive 16 bit processing pipe with gimp workflow integration and batch mode.

Photivo tries to provide the best algorithms available; even if this implies some redundancy. So, to my knowledge, it offers the most flexible and powerful denoise, sharpen and local contrast (fake HDR) algorithms in the open source world. (If not, let’s port them 😉 ) Although, to get the desired results, there may be a quite steep learning curve 😉 .

Photivo is just a developer, no manager and no “Gimp”. It is intended to be used in a workflow together with digiKam/F-Spot/Shotwell and Gimp. It needs a quite strong computer and is not aimed at beginners.

Processed with Photivo

Basically it’s an image processing assembly line. You set the parameters, throw your RAW file in on top, wait for a moment and catch your image when it falls out of the machine.

Today I give it a try and rescue an image of a kite with it. It’s an impressive tool with a quite unique but understandable user interface. I’ll explore this further, perhaps it will enter my workflow.

The companion file contains both used RAW files and all the setting files created by Photivo.

Sorry, there is no TOC up to now.

Kite

JPEG out of camera

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Meet the GIMP Video Podcast by Rolf Steinort and Philippe Demartin is licensed under a Creative Commons Attribution-Share Alike 3.0 Germany License.
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Episode 134: Dynamic Range T(h)errory

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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.

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Episode 114: Secrets of a Portaloo!

114
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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

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Meet the GIMP Video Podcast by Rolf Steinort and Philippe Demartin is licensed under a Creative Commons Attribution-Share Alike 3.0 Germany License.
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Episode 076: UFRaw revisited

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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

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Episode 043: Brand New and Stone Age

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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.

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Raw Therapee – Experimental RAw Photo Editor

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.

Episode 015: RAW to the rescue! Mini-HDR ;-)

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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.

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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.

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Episode 012: RAW, JPEG, TIFF????? What? When? Why?

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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.

cloud450.jpg

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

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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.

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