In Photos dot org

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:

1. The Levels tool on gimp.org docs
2. 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…

Children at play

A sign in Fermoy, Co. Cork warns motorists to watch out for kids playing on the road.

I’ve seen so many people speed through built up areas these signs mean absolutely nothing to them.

Technique:
1. Original image was flat and plain. Background sky was monotonous so I ran it through auto-levels which brought out the colours.

2. Then I duplicated that layer and blurred it using Gaussian Blur with a radius of 25px (original image is 3504px wide). By adding a layer mask I was able to rub out some of the blurred layer to expose the sharp original below. Opacity was set to 41% to reduce the blur effect.

3. Finally an overlay layer was added and circular gradients drawn on with a low opacity. This darkens the sky and sign slightly in patches.

All manipulation done in the GIMP but will work just as well in Photoshop or other application.

Was that useful? Want more?

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!

Cork City Tour Bus

The Tour Bus just left without me! An open top bus brings tourists around the city, where to? I’m not sure, I’ve never taken it!

This was on Grand Parade about 9 months ago. The plastic dividers in the middle of the street are now gone and where that bus is driving is now pavement, with the odd road works still going on.

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)

Shadows of prison and freedom

A crow flies off into the freedom of the air with a crumb of bread he found on the pavement. The railings of nearby houses are like those of a prison keeping humans in and trapped and closed off.

Who is free?