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Entries in the ' Gimp ' category
Written February 11, 2008 in Gimp, Gimp Tutorials, Photography, Words
Many people find using the GIMP or Photoshop a daunting prospect but in fact those packages are quite easy to use once you’ve practiced a few times. This will be the first in an occasional series to help photographers use the GIMP to post process their photos.
The Levels tool (right click on your image, select Colors, then Levels) is used to adjust the levels of the colours in your image by manipulating a histogram representing the image. In simple terms, you can make broad changes to the Red, Green, Blue and overall “Value” parts of your image.
The single most useful function of the Levels tool is the “Auto” button. Click that button and the histogram will be stretched out. Your image should look better. If the photo lacked contrast, it can suddenly become a lot “punchier”!
Here’s an example which will make things clearer.
This is a nice photo I took in Galway in 2005 with a Sony 717. Unfortunately, there’s a nasty yellowish sheen to the image. I probably shot this with the white balance set to cloudy. That can give a pleasing golden look to images but it’s not always welcome. The image also lacks contrast and looks under exposed. How do I fix that?
Fire up the GIMP Levels tool. Right click on the image, go to Colors, then Levels. This is the histogram for the image above. See how it’s all bunched into the middle? Now, click on the “Auto” button.
Wow! One click did that? The image looks so much better now! The swans actually look white and it’s brighter and shiny!
I opened the Levels tool again, just to see what effect “Auto” had on the histogram. Sure enough. It’s stretched from side to side.
Before and After Auto Levels
Wasn’t that easy?
Advanced Usage
You may have noticed the eyedropper buttons next to to the Auto button. Those are “Black”, “Grey” and “White” selectors. Click on one of those, your cursor will change to a eyedropper and then click on the corresponding colour in your image. They work pretty well, but can be confused. If it all goes wrong, just click the Reset button, or CTRL-z to undo if you’ve clicked OK.
You can also manipulate the histogram manually. Just drag the sliders left and right until your image looks ok. You can change the channel with the drop down at the top of the Levels dialog. Changing individual channels does interesting “cross processing” things to an image.
External links:
- The Levels tool on gimp.org docs
- Levels Tool - white, black and grey to the rescue! - a tutorial I wrote about the levels tool back in 2004!
Want to know more? Leave a comment. I’d love to hear what you’d like to know and learn about the GIMP.
The new release of GIMP 2.4 is finally out! Sven announced it on the Gimp User mailing list this morning. It seems like forever since 2.2 was released but he has promised that 2.6 won’t be as long in the making.
The roadmap for GIMP 2.6 will be discussed over the next weeks on the gimp-developer mailing-list. We can only tell you so much now: It is going to rock and it shouldn’t take as long to get it done as it took to finish GIMP 2.4. If you want to join the effort, your help is much appreciated.
GIMP.org is fairly slow now but the release notes have the low down on changes since 2.2. Some of the biggest user visible changes include red eye removal, healing tool and a better alignment tool. Plugins and scripts now live in the same place, the “Filters” menu. I’m using the rc3 release in Ubuntu Linux 7.10 and it’s been rock solid for the past few days. I’m sure Ubuntu will update their .deb package in the next few days.
After you update, get the GIMP Lomo plugin I posted yesterday. It’s 2.4 ready! 
This is a slighly modified version of an old GIMP Lomo plugin I’ve used for ages that will now work with the new GIMP 2.4 release thanks to some advice I remembered reading on the GIMP User mailing list. The original plugin is by Francois Le Lay but hasn’t been updated since 2005. It’s a basic script but it’s very effective. Just be warned, if you resize your image, make sure you right click on the Vignette layer and click “Layer to image size” before the resize. Otherwise odd things happen!
Download
Download gimplomo.scm.
Install
Installation is easy. Simply copy gimplomo.scm into your .gimp-2.4/scripts/ folder and restart the GIMP. It will appear as Image->Filters->Light and Shadow->Lomo.
Example Images
Below are two before and after examples of what the Lomo plugin does to images. I have also posted fake lomo photos in the past which should give a really good idea of what it’s capable of.
Before and After Lomo images
Why the change to Script-fu?
Script-fu in GIMP 2.4 requires that variables be defined before using them which has broken a lot of Script-fu scripts unfortunately. In theory it’s a great change because it tightens up on sloppy programming but it hurts the end user!
I wanted to take it easy tonight. It’s been a long week but here I am still. 16 photos worked on in the GIMP and ready to upload. You’re in for a treat next week with some of my shots from Kerry, even if I do say so myself!
Some people find the name of the most popular open source and GPLed image manipulation program slightly funny or rude, others as a derogatory term, while others just see it as the acronym for GNU Image Manipulation Programme. I think a lot of English speakers fall into the first or second camp unfortunately.
Wikipedia has all bases covered, from the sadomasochism definition to the more familiar GIMP definition.
Gimp is a usually derogatory term used to refer to a (male or female) sexual submissive person, typically dressed in black leather (or rubber), often in a gimp suit, and wearing a bondage hood or mask of the same material. This apparel emphasises sexuality by drawing attention to the crotch and chest, and also sexually objectifies the wearer. Sadomasochistic practice often features in the notion of the gimp, with a partnership of power exchange between gimp and dominatrix or dominant. It can also imply that a male has a smaller than usual penis.
Yeah, I use the Gimp to draw everything…
My favourite post-processing application, the GIMP, featured highly on a recent Digital Photography School survey. Here are the top 5:
- Lightroom
- Photoshop CS2
- Photoshop CS3
- GIMP
- Picassa
It just goes to show that price isn’t everything because a lot of people must have deep pockets to pay what Adobe charge for their products.
I also feel encouraged to write more GIMP tutorials now!
Joy of Tech makes a good point about the pricing of Adobe products. If you can’t afford to buy a copy of Photoshop then give the GIMP a go. It’d free, it’s what I use to process all my photos and it has many of the features most people need. (via)
I just read that a portable version of image manipulation program, GIMP, is now available for download.
If it works well enough that’s going to get a permanent home in my USB memory stick and unlike “Portable Photoshop”, this one is completely legal to copy and share.
GIMP Portable version 2.2.13 has been released. GIMP Portable is the full-featured GIMP image and photo editor bundled with a PortableApps.com launcher as a portable app, so you can edit your photos and images on the go. This new release updates the included GIMP to 2.2.13, adds Vista compatibility, correctly cleans up GTK’s bookmark and thumbnail files and features a greatly improved startup speed thanks to the new launcher’s plugin processing.
Written December 26, 2006 in Architecture, Canon 20D, Cork, Gimp, Ireland, Landscape, Long Exposure, Night, Photos, River Lee, Sigma 10-20, Urban
The River Lee rushes by the Beamish and Crawford Brewery on one side, and O’Sullivan Electrical on the other with St. Finbarre’s Cathedral in the background.
I have discovered there’s a dead pixel on my camera’s sensor. Fortunately it doesn’t seem to show itself much but when I take long exposure shots like the one above a little red dot appears in the top-right of the image. It’s easy to get rid of with the clone tool but also annoying.
The Wacom graphics tablet is great fun to play with but I haven’t got it working fully in Linux yet. Ubuntu thinks it’s simply another mouse device and GIMP doesn’t see it as an “extended device”. I spent quite some time on the Ubuntu forums trying to fix it yesterday before giving up and trying it out on a few images.
It’s a little fiddly to begin with, but I think that’s par-for-the-course when using a new tool. I do find that when dodging and burning large sections of images the brush can get stuck and won’t follow the cursor but I’ve read that once it’s properly configured performance is improved so I hope that is fixed then.
Hope you had a nice Christmas Day!
It may be possible to get Photoshop to run in Linux but would you want to? As a research project in the interest of informing the dear readers of this blog I attempted the install.
- First of all I had to search out an illegal copy of Photoshop because frankly I don’t have Photoshop and can’t afford it given the revenue I get from my photography. Bittorrent helpd here but, boy was it a pain. There’s a version of Photoshop floating around called “Portable Photoshop”. It’s a self contained install. Unfortunately I got hopelessly low download rates for the several torrents of this application I tried. Adobe, you have nothing to worry about!
- While that was downloading I installed wine with a simple
apt-get install wine. No surprises there. Apt did it’s job and installed everything properly. - Finally, the necessary bits downloaded and I unzipped it into a directory then ran
wine Photoshop.exe.
How well does it run? After running Wine, up popped the Adobe loading screen and for what seemed like an age it looked for plugins and other assorted stuff. Finally, after a significant wait the Photoshop user interface appeared and I marvelled at how far Wine has gone since I last tried to run Half Life 2. First thing to do was load an image so I clicked File-Open, selected a file and clicked OK. Then, poof! An out of memory error popped up and Photoshop died!
After closing Firefox and Thunderbird I tried again. This time the image loaded but as soon as I tried any operation on it the same error popped up. After briefly searching for an answer and looking through the winerc, I didn’t bother trying a third time. Even if I didn’t have these memory problems I wouldn’t find myself using it. It doesn’t match the rest of the desktop. It’s dog-ugly actually. Windows apps usually are when they’re running in Wine. Bye bye Photoshop! It’s now deleted off my drive.
Linux users - Ubuntu, Debian, Gentoo, Slackware, Red Hat, whatever you use, just use the GIMP. It’s a great piece of software that’s simply different to Photoshop. That doesn’t make it necessarily worse. If you are really hankering after the Photoshop UI then go play with Gimpshop. You’ll feel right at home in no time and you’ll save the 833 Euro that Adobe charges for their cash-cow. Ouch! How can any non-professional afford that?
Oh, Sven is working on colour management for the GIMP to keep all you printing folk happy!
Another alternative, Krita has come a long way since I looked at it last. I installed it this morning using Edgy’s Apt repository and it looks good. From a photographer’s perspective it’s missing a few necessary tools, although a levels tool is in the works. It does have support for CMYK but I’ve never had a use for that and as Cyrille says, all home and business printers use RGB. Some high end printers use CMYK but your local lab will print from Jpeg files so don’t lose sleep over it! I must post a comparision between the GIMP and Krita when I’ve used it before.
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