The GIMP is the GNU Image Manipulation Program, it as a well-developed tool for creating and editing still images, such as graphics or photographs. There are many excellent turorials available for the GIMP on the web, such as:

The next thing to note before we really get started, is the GIMP toolbox to the left of your screen.

The GIMP toolbox is divided into two sections, with the individual tool icons displayed at the top, and the contextual tool options below.

The 'File' menu at the top of the palette is where we will start with opening and saving files.

Just below, you can see the tool icons. Whenever you select a tool from the palette, the options menu below it will change enabling you to adjust features specific to that tool, such as brush size and opacity.

If you hover the mouse pointer over any icon in the toolbox, a small descriptive popup will appear to let you know what that tool does, which is helpful.

In between the toolbox icons and the tool options, you can see two colour and pattern related panels.

In Fig 2 we can see that the foreground or active colour is set to black, and the background color is set to white, so in this example the toolbox is selected to get us started with an black 11 point brush size.

Open, Resize and Save Images

Let's start with a really simple everyday operation. Let's assume you have already scanned a photograph or have it on file, and you want to open it up in the GIMP, resize it, perhaps for the web or to send by email, and save it again.

Choose 'File > Open' from the top of the toolbox to access the Open Image dialogue box (Fig 3). From here you will be able to drill down through your local folders to select the image you wish to work with. Once you have found it, select 'Open'.

With the selected file now open, select 'Scale Image' from the 'Image' options menu, as in Fig 4, below.

The 'Scale Image' dialogue will appear giving you several options for manupluating the size and resolution of the image. See Fig 5.

A common operation is to ensure that scanned images are set with the correct resolution for adding to a web page.

Photographs are normally scanned at around 150 pixels/inch (or DPI, 'dots per inch'). If you want to put your image on a web page, you'll need to reduce the resolution to the standard monitor resolution of 72 pixels/inch for it to display on screen with the expected dimension.

In this example, we are also reducing the dimensions of the image down to a width of 640 pixels by altering the width and height in the 'Image Size' options.

Note that the mouse pointer in Fig 5 is clicking on the 'chainlink' icon? This is to ensure that the height of the image will be automatically set in proportion to the specified width.

Finally, click the 'Scale' button on the bottom right of the 'Scale Image' dialogue box, and the image will change size.

To view the image at 100% of its actual size, click on the 'Zoom' menu on the bottom left of the file window as in Fig 6, and select 100%. This is a useful menu to know about for getting more or less detailed views of the image.

Finally, to save the image, select 'Save As' from the 'File' menu either at the top left of the image, or at the top left of the toolbox, navigate to the folder where you wish to store the image using the 'Save As' dialogue box, and click 'Save'.

In this instance when you name the file, give it the suffix “.png” for JPEG, which is the best file format for photographs. The GIMP will detect the file suffix and automatically walk you through some of the JPEG format options. You should nly need to click OK for the defaults, unless you wish to reduce the file size by reducing quality.

We have now successfully opened, scaled and saved an image.

Let's move on to 'cropping', or cutting out a small section of the image to save as a separate file.

Crop Images

In this section we are going to use the 'Rectangular Marquee' tool to select an area of the image, and then reduce the size or 'crop' the image to the selected area. Firstly, select the Rectangular Marquee tool from the toolbox;

Check that in the tool options palette below, the option is set to 'Free Select' enabling us to draw the rectangular area we want. Alternative options enable you to specify a fixed pixel size, or fixed aspect ratio for your selected area.

With the rectangular marquee tool selected, click and hold the mouse pointer where you want the cropped area to start, and, still holding the mouse button, drag the pointer to create a selected area, releasing the mouse button when you have the desired dimensions.

The selected area will be highlighted with a dotted marquee as in Fig 8, below.

If you make a mistake with the dimensions or positioning of your rectangular marquee, choose 'Deselect' from the 'Select' menu at the top of the file window, and start again.

To crop the image, click on 'Crop Image' in the Image menu at the top of the file window. See Fig 8.

When 'Crop Image' is clicked, the area outside of the marquee selection will be discarded, and the image will be reduced to the selected size. See Fig 9.

Remember to choose 'File > Save As' at this point, and give the cropped file a different name when you save it. Save it as a “.png” file again.

Adjust the Image

Imagine that the image you have scanned, scaled and cropped so far is a little 'off colour', perhaps it's a little dark, or the colour balance just doesn't feel right. Most graphics packages, including the GIMP, will enable you to make some fine grained adjustments to the image quality.

In this section, we'll introduce the 'Tools' menu, and show you how to quickly and simply adjust the 'Levels' in your image to apply some basic colour correction.

To get started, select the 'Tools' menu from the top of the file window. You will notice that there are several things you can do under the 'Colour Tools' menu. Don't be afraid to experiment when we've done the very basics here.

Select 'Tools > Colour Tools > Levels'. Levels enable you to examine the color/grayscale spectrum, and make changes based upon the individual image.

Depending on the original quality of the scanned photograph, you should see some improvement in the image as it previews the changes for you. Click 'OK' to save the changes.

There are plenty more colour correction efffects you can apply via the 'Colour Tools' menu. The best thing to do is to dive in an experiment.

If you make a mistake, or don't like the look of the effect you have applied, select 'Undo' from the 'Edit' menu.

Experiment with Filters

Now for the fun part. We're going to take a look at the GIMP 'Filters' menu, and apply a special effect to the image.

The GIMP comes with a wide range of cool filters, enabling you to warp, twist, blur and mutate your image in any manner of ways.

For this introduction to filters, select 'Filters' from the file window menu. As in Fig 12, you can see a wide range of filter types to experiment with. They all work in pretty much the same way. Selecting a filter from the drop down menu will result in a pop up contextual dialogue box, enabling you to adjust the settings for that particular filter.

In this example we are going to choose the 'Oilify' filter from the 'Artistic' section of the filters menu. Fig 13, shows the Oilify dialogue box, where the intensity of the filter can be adjusted by using the 'Mask size' slider, or by entering a number into the box.

Click 'OK' to apply the filter. Again, if you don't like it once it has been applied, you can select 'Edit > Undo' to revert to the unfiltered image.

Now save the image, but this time choose 'Save As' and give the file name the suffix “.gif” for 'Compuserve GIF'. The GIF file format is ideal for less detailed images with blocks of colour, particularly logos and non photographic images for web pages.

As when we saved as '.png' the GIMP will again detect the file format from the suffix, and take you through a few wizard screens on which you can generally just click 'OK' to select the default values for now.

Using the GIMP Dialogue Panels

In this section we are going to open up a few 'dialogue' panels in preparation for adding some text to our image.

The particular dialogue panel we are interested in is the 'Layers' panel. We'll look at layers in more detail in the next section.

At the top of the file window you will see a 'Dialogues' menu. (See Fig 14). Click on this to see the range of dialogues available to you. Selecting any item from this menu will pop up a special floating dialogue panel with tools that you can keep to hand over on the right hand side of the screen.

Dialogue panels can provide useful additional on screen shortcuts for tool options, like fonts, brushes and colours. Dialogue panels can be moved around the screen by clicking, holding and dragging the top of the panel window as in Fig 15 below.

Bring up the layers dialogue panel and position it to the right of the image you are working on, ready for use in the net section.

Fig 16, shows that you can have several handy dialogue panels open at the same time.

The layers dialogue is probaby gthe most important and useful one to have open all the time as we shall see.

Here we have also opened the foreground/background colour dialogue and moved it into position over the layers dialogue to create a tidy workspace. You can place your dialogue panels anywhere on the screen, but stacking them up over on the right hand side makes for a tidy workspace.

With the fonts dialogue open as welll, we have a collection of useful tools on screen and ready to use.

Adding a Text Layer

Layers enable you to add to detail to your graphic such as text, other images or masks layer by layer, a bit like laying overhead projector transparencies on top of each other. GIMP layers are also transparent.

The advantage with layers is that you can easily build up a composite image, add effects and filters to individual layers, show and hide individual layers to experiment with different combinations, and delete layers that you do not wish to use.

In this section we will add a text layer to the graphic we are working on.

With your graphic open and ready to work on, and the relevant dialogue panels open as well, your GIMP workspace should look something like Fig 17.

First of all, we are going to choose a colour for our text from the FG/BG dialogue.

Click anywhere on the vertical spectrum on the dialogue panel to get the colour range.

Then click within the hue palette to select the colour you require.

In this case, the mouse pointer has clicked in the white area towards the bottom right of the hue palette. (Fig 18).

You should notice over on the toolbox, that the foreground colour on your FG/BG colour indicator switches to the colour you just selected. (Fig 19).

Next we need to choose a font to add to our text layer.

One way to select the font is via the Fonts dialogue.

Scroll up and down until you see the font you require and then click on it. (Fig 20).

You will notice over in the toolbox font options panel, that the selected font appears.

Next, click on the text too, in the GIMP toolbox, and with the text tool selected, click anywhere on your graphic to add a text layer.

You will notice that the GIMP text editor pop up appears. Add your text into the input area, and watch as it appears on the graphic in the font and colour you selected earlier.

Notice also, in the Layers dialogue, that using the text tool has automatically added a new text layer, and that the layer is highlighted as the 'active' layer. (Fig 23).

Each time you add text it will be put into a new layer. To edit the text later, select the appropriate text layer in the Layers dialogue by double clicking on it, and the GIMP text editor pop up will appear again.

Now we are going to add a filter just to this new text layer, not to the background layer underneath.

Make sure that the text layer is still selected in the layers dialogue, and then choose 'Filter > Distort > Curve Bend' (or any other filter you wish) from the file window menu.

The curve bend filter is shown being applied to the contents of the text layer in Fig 24.

Experiment with moving the curve points in the filter pop up, and click OK when you are finished.

Finally, with the text layer still selected, click on the 'Move' tool in the GIMP toolbox, and click, hold and drag on the text within the dotted marquee on the graphic to move it into position, as in Fig 25.

Wicked! You now have a simple graphic, cropped from a larger photographic image, with a filter applied, and a warped text layer.

Don't forget to save your file.

In this short tutorial, we have only scratched the surface of what the GIMP can do, but we hope we have demonstrated enough of the key, everyday features in a practical and useful manner that will enabvle you to reproduce the results in this tutorial and gain enough confidence to explore further on your own. Enjoy!