GIMP, or GNU Image Manipulation Program, is a free open source graphics editor originally developed for Linux but now also ported to Windows and Mac OS X. This free graphics editor has been around for a long time and it is a feature rich graphics editor that has all the tools and filters needed to do a lot of photo retouching and editing.
In this tutorial I will teach you the basics of GIMP such as resizing and cropping images, adjusting brightness, contrast and colors. Also we will look into adding text, rotating images, removing backgrounds and an introduction to how you can use layers.
You can download GIMP here.
To resize an image with GIMP, go to the ”Image” menu and select ”Scale Image”. Here you can select a new size for your image.
Once you’re done, click on ”Scale” and your image will be resized.
Brightness & Contrast Adjustment
If you want to adjust the brightness and contrast of your photo, go to the ”Colors” menu. Once there, select ”Brightness-Contrast”.
Then make your desired adjustments, you will see the results live on the image. Once you’re done, click ”OK” to apply the adjustments.
There’s a couple different filters to adjust colors. They can all be found under the main ”Colors” menu. First we’re going to look at color balance, which allows you to adjust color levels for shadows, midtones and highlights.
Next we’re going to look at hue, saturation and lightness adjustments. By increasing saturation for example, you can adjust the strength of the colors in a photo. You can also adjust saturation only for a specific color that you want to bring out or tone down. Adjusting the hue will change the colors of your image, this setting can also be applied to a specific color.
The third way to adjust colors is by colorizing your image. This basically turns the image into only one hue of colors. It’s kind of like making it greyscale except tinted with another color. If you reduce the saturation to zero it does become greyscale.
Another way to mess around with colors is by adjusting color levels.
And the last filter I’m going to mention regarding color adjustment is color curves.
To add text to an image select the text tool from the left menu. It has the symbol of the uppercase letter A. Then select an area on the image where you want the text to initially appear. This can be done by left clicking the image and holding the mouse button down while dragging the text field to cover the area where you want the text. The text can of course later be moved around.
Then just type your text in the text field. If you want to change the color, font or size, just highlight it and use the menu above the text field to make your adjustments.
To move the text you can then use the movement tool from the left menu. It looks like a cross with arrows pointing in each direction.
To make a simple and quick 90 or 180 degrees rotation on your image, go to the ”Image” menu. Then go down to ”Transform” and there you can select in which direction you want to rotate it 90 degrees or 180 degrees. You can also use the rotation tool from the tool menu, but this option will not rotate the entire image.
Cropping an image is easy with the cropping tool, you can select it from the left menu. It looks like the head of a scalpel. Simply use your left mouse button to click, hold and drag it across the area you want the image to show. The rest will be removed once you’ve selected the area and press ”Enter”.
Removing or cutting out the background or parts of an image can be done with the selection tool. You can find on the left menu with all the other tools, it looks kind of like a lasso.
First find the area you want to remove or cut out. Then left click on the place where you want to start, go to the next spot and left click there and just repeat this untill you’ve covered the entire area. Once you’re done, click on the spot where you started to complete the selection.
Now you can either press ”Delete” to remove the area, or ”CTRL-C” to copy the selection. This copied selection can then be used in other images as a layer or saved separately as an image file.
Layers are very useful, they allow you to independently move and adjust different parts of an image like a text selection or a cutout. You can see the layers on the upper right area of the default interface.
You can make new layers by clicking the icon that looks like a blank sheet of paper on the lower left of the layer menu.
In the video I copied a cutout and pasted it on to a new layer. I was then able to move it around and make adjustments to the cutout without affecting the rest of the image.