Episode 178: Lurking in the Shadow

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You are in for a night-time trip to one of the most secret places on the earth – until 23 years ago. The former Stasi headquarter is only 2 subway stations east of my home and I quite like the morbid, spooky atmosphere there. It’s a really huge areal, lots of office space and other buildings. Some of them are used as a museum and as the archive for all the Stasi files. Others are rented out or are simply empty.
My image missed some details in the shadows. I used a modified “burn with a layer in Overlay Mode” technique to get a bit of light into them. Instead of painting on the layer I used the L-part of the LAB colour model. I got the idea for this from the Darktable Blog.

UPDATE Mar 18: There is a nice way to use the histogram with selections. Select the dark region and look at the histogram – it shows only the data from the selection. The histogram tool is “selection-sensitive”.

Thanks to GIMPel for the tip.

The TOC

00:30 The Stasi Headquarter
05:00 Start of the image processing
05:20 Rotate the image – what is vertical?
08:00 Cropping
09:40 Planning where to work on the shadows
10:00 Measure the darkness with curves tool
10:45 A quick try with the curves tool
11:30 A layer in Overlay Mode to brighten shadows up
12:00 Decomposing the image to get the “L” from LAB
14:30 Invert the colours
14:50 Generate a layer mask
15:50 Constructing the “Lighten Only” layer
17:00 Optimizing the effect
17:50 Blurring the overlay layer improves the effect
22:30 Compare to simple burning
24:50 Recap
27:45 http://darktable.org gave the idea to this

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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.

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

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.

Digital face powder – in Overlay Mode!

I shot pictures of my colleagues at work for a farewell book. One image came out with a real drunkards nose – much too red. Not so nice.

I just doubled the layer, inverted it (Color/Invert) and set it to overlay mode. Ghastly. Then I added a layer mask in black, (hiding everything) and painted with a soft brush in white (with low opacity) over the nose. Worked really well. Gradually the skin looked better. This worked too on some blotches on the skin.

Sorry, I can’t show the image here.

Episode 051: Contrasts from Belize

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As I should have known, Belize is a small country in middle America. Next to Mexico and Nicaragua. I should have known because our fair traded Bananas are from Belize. But this video is not about Bananas, it’s about this image made in the shadow on a bright tropical day.

You see the problems in the original top-left. The background is a bit too bright  and the woman way too dark. But two layers in overlay mode of an inverted desaturated copy of the image helped a lot. The final touches came by applying a layer for dodging and burning, also in overlay mode, and painting on it in white. All Croat to you? (Not Greek this week, see this blog entry.…) No problem, after the video you’ll understand.

Overlay mode does strange things, even the explanation in the help pages is a bit cryptic: “Overlay mode inverts the pixel value of the lower layer, multiplies it by two times the pixel value of the upper layer, adds that to the original pixel value of the lower layer, divides by 255, and then multiplies by the pixel value of the original lower layer and divides by 255 again.” I’ll think about a way to get that a bit easier to swallow.

The Linux Darkroom is an interesting collection of links and program descriptions. Definitely worth to look at – and perhaps you have something to add.

You can find the file used in this episode at the usual place.

The TOC

00:18 Off to Croatia – Slobodni Festival 2
02:02 The Linux Darkroom
02:40 Geography Lesson
03:22 High contrast image from Belize
06:04 – Try curves adjustment
07:48 – Overlay layer
08:47 – Overlay in monochrome
11:36 – Selective tweaking
17:12 Thoughts about episodes 50 and 49
20:39 The End
TOC made by paynekj

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Creative Commons Attribution-Share Alike 2.0 Germany License.