Gimp tutorial: This is how image editing works with the free tool

Gimp tutorial: This is how image editing works with the free tool

With our Gimp tutorial you will learn the most important functions of the free image editing program. Whether you want to crop, rotate, reduce or crop an image – here you can find out how to do it. And more.

Download and install the Gimp

The free image editing software Gimp is available for Windows, GNU / Linux and macOS. You can download the software from the provider and simply follow the installation process.

Download : Get Gimp at gimp.org

Open an image in Gimp

Before opening a picture in Gimp, you should make a copy of the picture. The changes you make to an image in Gimp are retained.

You open an image in Gimp with the command "File> Open". Find the folder the image file is in and select it. Gimp can open images in many different file formats. For image processing, RAW files with the raw data are more suitable than JPGs or PNGs.

Shrink and rotate an image in Gimp

gimp-image-scaling-2

You change the image size with the command "Scale image". Picture:

To reduce or enlarge an image in Gimp, go to "Image> Scale Image". Enter the desired "width" and "height" and confirm your choice with "Scale".

Instead of "px", ie pixels ", you can also specify the size according to millimeters, centimeters and other scales by clicking on" px "and making the desired choice. Please note: If you enlarge an image, it will deteriorate Picture quality.

To rotate an image, go to "Image> Transformation". Then you choose "Rotate 90 ° clockwise", "Rotate 90 ° counterclockwise", "Rotate 180 °" or "Rotate at will". Under "Rotate at will" you choose the desired angle yourself and confirm your choice by clicking on "Rotate".

Crop an image in Gimp

gimp-picture-crop-cut-out

You need the appropriate tool for cutting. Picture:

You can also crop or cut out a part of an image in Gimp. This is useful if you don't want to edit the entire image, but only part of it. Go to Tools> Transformations> Crop. A selection square now appears, which you can enlarge and reduce by clicking and holding on the corners. Everything around the square is darkened. If you click in the middle and hold down the left mouse button, you can move the selection square.

Once you have selected the desired part of the image, confirm your choice with the Enter key or click on it with the left mouse button. The image is now cut out as desired, the area outside the selection square disappears.

Adjust colors and contrast in Gimp

Often times a photo looks wrongly exposed or does not have the right color or lighting mood. The menu item "Colors" opens up numerous possibilities here. Under "Colors> Automatic" you will find a number of options, such as automatic contrast matching and color enhancement. You can try that out and if necessary undo the step via "Edit> Undo". Often times you get better results with manual settings.

gimp-image-brightness-contrast

You adjust brightness & contrast with the help of the slider. Picture:

Under "Colors> Exposure" you move the bars for "Black Level" and "Exposure", whereby you can observe the effect of the planned changes on the image as a preview. With the arrows on the right on the bar you can also take small steps or type in values on the keyboard. Confirm your choice at the end with "OK". Options like "Brightness / Contrast" and "Color Balance" work on the same principle.

Setting the "color values" works a little differently. Here you have three controls under "Source values". You'll need to move the left and right sliders until they hit the first white pixels on the left and right. The darkest part of the image is set to 100 percent black and the lightest part to 100 percent white.

Remove contaminants in Gimp

gimp-picture-cure

With the "Healing" tool you remove dirt on the picture. Picture:

To remove dirt on the picture, for example from a dusty lens or a stain on the subject, there is the "Heal" tool in Gimp. You can find it under Tools> Painting Tools> Heal. Adjust the size of the selection circle to match the size of the smudge. "View> Fullscreen" or zooming in via "Ctrl + mouse wheel" may help. To change the size of the selection circle, tap the keys for the square brackets "[]" ("Alt Gr" + "8" or "9").

Hover over an area next to the stain that looks similar and doesn't have any stain. Tap on "Ctrl + Left Mouse Button". Click on the stain and it should go away. Otherwise you can hold down the mouse button a little and paint over it. The tool copies the previously selected pixels to the new location.

Remove the background and crop images in Gimp

gimp-image-background-clipping

Choosing the background can be a challenge at times. Picture:

You can remove the background of an image and replace it with another in Gimp. For example, you give the impression that you were not at home but on vacation in the Maldives. In principle, swapping the background is easy – but doing it accurately and credibly can be quite difficult.

First go to "Layer> Transparency> Add Alpha Channel". Then click on "Tools> Selection Tools> Foreground Selection". Now select roughly the foreground by "painting" it with the mouse button pressed and pressing "Enter" on the keyboard. This separates the foreground from the background. Now paint by holding the left mouse pointer over the background and try to hit everything as precisely as possible. Confirm "Enter" when you are done.

You can also use the wand as a tool if that's easier. You can find it under "Tools> Selection Tools> Magic Wand". The magic wand selects areas of a similar color. Add further areas by holding down "Shift" and tapping on a new area. When you are done, click on "Del" on the keyboard, ie "Remove". Now the background is removed.

Add another background by copying an image onto a new layer (Layer> New Layer). Go to "Layer> Stack> Layer to the bottom" to move the layer under your picture and use it as a background.

gimp-image-background-cropping-2

Here the background has been replaced (not quite perfect) with a white layer.

Summary

  • Gimp is available for free at gimp.org .
  • You open a picture with "File> Open".
  • You change the image size with "Image> Scale Image".
  • You can rotate an image under "Image> Transformation".
  • The cropping works with "Tools> Transformations> Crop".
  • Under the menu item "Colors" you can adjust exposure, contrast, colors and similar aspects.
  • The "Heal" tool under "Tools> Painting Tools> Heal" is used to remove impurities.
  • Cropping motifs and removing the background require several commands and often manual detailed work.

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