Introduction to image editing with Gimp
Gimp is an image editor which is as powerful as Photo Shop but has the great advantage of being free whereas Photo Shop will cost you many hundreds of pounds. The other advantage is that Gimp will work not only with Linux based operating systems, with which we are primarily concerned, but also with Windows and Macs.
To show how the Gimp works, the basic examples relate to the toolbox and menus. To show how the various tools may be compared together, more extensive examples are provided loosely grouped by the graphic categories of
- Photo or image editing
- Art and graphic design
- 2D animation
By working through various examples, our comments should equally apply irrespective of the operating system you are using. As Linux users ourselves all the examples show here were produced on either Linux Ubuntu (10.10) or OpenSUSE (12.3) operating systems. As well as the tutorials you can see here, there are more on the Gimp Website -www.gimp.org
If you now open Gimp, version 2.6 by default here, you will see three separate panels, one on the left, one on the right and one in the centre.
The left panel has two sub-panels, an upper Tool panel and depending on which tool is selected, the lower Tool Option panel. In the Tool panel there are a number of icons each representing a tool to be used and when you click on a tool various options appear for that tool in the Tool Options panel. Try clicking on the icons and you will see the options change as different icons are selected.
The right hand panel can be customised to suit your particular needs, but initially there are some default options, such as layers. In this panel the icons are arranged as tabs along the top, and like the tool panel, the main part of the panel will vary depending on the tab selected.
The central panel is the Image panel and it is here that an image is located to be worked upon. When the GIMP is presented on first launch, it will default to the three separate panels. This is the Multi-Window Mode.
Single window mode – Docking panels
Since version 2.8 of the Gimp, you may toggle between floating panels or single (e.g. Photoshop style) window to find your preferred presentation. The required setting can be found in Windows –> Single-Window Mode
Depending on your work flow, you may find the single window mode is more convenient, especially if you have have several different applications open at once.
Customising the GIMP
For tools you frequently use, these can be added to the right hand panel, using the dockable dialogues, under Windows in the main menu.
As you can see there are quite a few options. Simple click on the desired option, and it will get added to the right hand panel.
If you prefer, you can drag the tag across to the left hand panel, using this for frequently used controls, and the right hand panel for occasionally used dialogues.
Loading an image
Now to illustrate just how Gimp works it is proposed to show you a number of basic operations which can be applied to an image. So firstly click on File on the Image panel and Open, then navigate to an image you wish to alter, highlight it, then open it and the Image will appear in the Image panel. Alternatively, you can open the image in a separate window and drag and drop it into the Image panel.
When initially loaded the image may not fill the whole of the centre panel. Using the menu bar View –> Zoom –> fit image to window (ctrl+shift +J) will zoom the image to better fit the window. Alternatively, and depending on whether the image format is portrait or landscape, you may use the View –> zoom –> Fill window option instead.
Now before starting it should be mentioned that throughout the description that follows reference is made to various tools you will find in the Toolbox panel. Looking at all the icons you may say well which is which? Well as mentioned above, firstly you will learn what the icons mean with use but in the meantime simply hover your mouse pointer over each icon and it’s description will appear.
Tools can generally be selected by one of three methods. The first, and probably the easiest is from the toolbox itself. Secondly the GIMP toolbox can be sub divided into the following menu sections, so the tool can also be selected via the menus
- Transform tools
Lastly in many cases, the tool can also be selected using a shortcut. Hover the mouse over a tool and a pop up menu will appear. This will show the short cut if one is available. The shortcut may be a single letter, or a combination of keys. For example the bucket fill is Shift + B (hold down the shift key and press B to select it). Pressing B by itself and you will select the the path (or Bezier) tool.
In addition are the colour tools, mainly associated with photo editing
Opening or Creating a new image.
To open an existing image simply click on File –> Open and navigation to where the image is stored., then open it. Alternatively if the directory where the image is is open, simply drag the image over an open copy of the GIMP.
To create a new image select File –> New to get the dialog options shown below.
Generally all you need to do is change the dimensions or orientation (landscape or portrait) of the new image, the default is pixels, but you can also set them to other units; mm for example. When you have made your choice click OK.
The save, or save as options under the file menu will save images using the GIMP’s xcf format. This is especially useful for work in progress, and for preserving the layers in an image file. It’s a good idea to save intermediate stages of editing, (e.g.by appending a version number to the filename ), so if necessary you can go back to a prior version if things go wrong.
Since Gimp version 2.8 however, to save an image in .jpg, png, gif or other format, you must now use the export, or overwrite File menu options instead, which can be found under the file menu. The file format you choose depends in part on what the image is to be used for.
Obviously the best place to start is the GIMP website itself where you will find the current help manual. There are also plenty of Videos and Tutorials on the Internet specifically for the GIMP, covering just about everything you need to know to create professional level graphics. Even Photoshop references with a little ingenuity can be adapted for the GIMP, so don’t underestimate it’s capabilities, just because it’s free (as in Open Source).
Be careful to make sure the tutorial, or video, applies to the version of GIMP you are using. Unfortunately the Internet is littered with stuff that has become obsolete, or just plain wrong.
In the main, it is an Image Manipulation Program not an Illustrator package, but some basic functions are included. The ability to draw lines and shapes for example.