GIMP: How To Edit Photos The Right Way

Photo by Mylene Tremoyet on Unsplash

GIMP is a tool for editing photos. It stands for GNU Image Manipulation Program. But it’s actually much more than that. GIMP can do all kinds of things beyond ordinary photo editing. Plus, the program was built from the ground up to help people who may not have the best grasp of photo editing software. For amateurs, GIMP really is the best.

But how do you edit photos using GIMP? Even though GIMP is so simple, it’s nice when somebody can explain to you the various tools in a simple and coherent way, and that’s what we’re here to do. We’ve put together this tutorial so that you can better understand GIMP, how to edit photos the right way. 

Step by step, you’re going to learn how to edit a photograph, from how to find your image in the first place to how to turn it into a masterpiece. This is the only tutorial you’ll need for GIMP. And believe us when we say, using GIMP is even easier than you think.

Step 1: Finding Your Image

The first step is to actually open your photo in the program. You’ll be dealing with JPEG or RAW files. If you’re taking pictures with your smartphone, the files will probably be JPEG.

Go to File, click the Open tab, then find your photo. On the left are all the locations your picture might be, from your computer’s hard drive to an external drive. Double click on the appropriate folder, then open the desired picture.

Step 2: Use Layers

Before you start editing the picture, make sure you duplicate it. It’s always good to save the original photograph in a duplicated layer. It keeps the original copy unedited while you work on the edited picture. You never know when you’ll need to go back and look at the unedited version.

To make a duplicate layer, click on the Layers panel, click on the photo in the Layer’s dialogue box, then click the Duplicate icon. Now you can rename one layer “edited” and leave the other alone as the original.

Step 3: Using the Levels Tool

With your edited photo selected as your active layer and open, it’s time to start. The Levels tool is one of the first ones you should consider using. The Levels tool allows you to adjust the brightness and the contrast of your picture.

Click on Colors in the top bar, then scroll down and click on Levels. This will bring you to the Adjust Color Levels box. You’ll see a histogram showing input levels and there will be a bar underneath for gradient. This is an accurate value of your original image in the form of a bar graph based on three things: shadows, highlights, and tones. 

If the graph is taller on the left, it means there are a lot of dark pixels in the photograph. The higher the graph, the darker the picture. Now, if you drag the triangular slider below the graph on the far left (the black triangle), it will brighten your photograph. If your photograph is too bright, dragging it the other way will darken it.

The gray triangle in the middle will adjust your mid-tones. Dragging it to the left will brighten while dragging it to the right will darken. The white triangle on the left will adjust highlights by shifting the white point. Move the triangle to the left to brighten and to the right to darken.

You can play with these three triangles to get different levels of brightness and contrast from your photograph.

At the top of the box where it says “Channel,” you can change the drop-down menu to “red.” This changes the red channel. Now instead of changing the brightness using the three triangles, you will be adding or removing red from the image.

You can do the same thing, changing the drop-down menu and playing with the three triangles in the green channel and the blue channel, changing the colors until they’re perfect.

Step 4: Changing Shadows

Go to the Colors tab menu, then find “Shadows-Highlights.” this tool lets you re-balance the photograph by adjusting shadows and highlights. In the box menu, you’ll see a box that says Shadows, a box that says Highlights, and a box that says White point adjustment. Increasing the level of shadows will bring out detail that was previously shadowed.

If you decrease the highlights, it will bring down the brighter values in your picture. Less than zero will decrease exposure while greater than zero will increase exposure. Then to shift the white point, going lower will darken the image by decreasing white pixels. Increasing the white point will increase the white pixels and make your image brighter.

Step 5: Saturation 

Find “Saturation” in the Colors tab menu. This option allows you to change the saturation, meaning the intensity of the colors. By moving the scale in the saturation menu all the way to the left, it removes all the color and can make your picture black and white. If you increase the scale of saturation, all the colors in your picture will pop and get brighter. Basically, this tool is for making your picture more colorful and bringing the colors to life.

Step 6: The Spot Heal Tool

The Spot Heal Tool is for correcting problems with the model in your photograph. The tool lets you fix things like scars, wrinkles, and acne. To access the Heal Tool, press the H key on your keyboard, hover over the Clone Tool in your toolbox, the icon that looks like a stamp, then select “Heal.” 

This tool works like a paintbrush. The mouse cursor is the brush head, which can be changed in the menu where it says “Brush,” either increasing or decreasing the size of the brush. You can change the hardness level of the edit in the menu where it says “Hardness.” Having the setting under 50 is recommended.

To heal the model, pick a source area by holding your ctrl key and selecting an area of skin where the person’s complexion is the ideal color you want. This is the color that will be used for the healing. Then all you need to do is click and paint with the brush, which changes the flawed pixels where the model has blemished skin with the color you chose earlier. The result should be that zits and scars are covered up with the color from the perfect complexion.

This can take a bit of practice, as you need to blend the healed areas to make them all look uniform and natural.

Step 7: How to Crop

Cropping your picture is pretty straightforward. The crop tool can be accessed by pressing shift + C on your keyboard. Now all you need is to draw your crop by clicking and dragging the mouse across the area of the picture you want to keep.

If you want to crop with a little more scrutiny, you can use the tool options to create a specialized crop area. You can maintain a certain aspect ratio by checking the box that says “Fixed” and choosing the aspect ratio from the box below it.

Step 8: How to Scale

Scaling your image is important. Depending on what you’re using the picture for or where it’s being uploaded, it needs to be scaled to a certain size. Go to Image in the upper menu and find “Scale Image.” 

Here you have options for width, height, X resolution, Y resolution, and quality. Changing the numbers inside the width and height boxes will change the size of your picture. You can also either lock or unlock whatever the current aspect ratio of your photo is by clicking on the chain-link icon beside the boxes. Keeping the ratio locked is important, that way you can change the width and the height will automatically change with it.

The X and Y resolutions dictate the image resolution in pixels per inch. This is an important thing to know about for people who are going to print their pictures. The numbers are converting digital pixels into physical inches. In general, 300 pixels per inch is very high resolution and is the recommended setting. However, if you’re not printing, this doesn’t really matter.

The quality section is how your photo will be scaled. By choosing “None” in the menu, you will get a serious drop in quality when your image scales. Linear or Cubic are better choices if you want something that scales quickly. But if you want the best image results, choose either NoHalo or LoHalo.

Final Step: Save & Export

Once you’re done, it’s time to save and export. Click on “File” in the upper corner and then go down to “Save.” You can change the name of the picture in the upper box, just make sure the file ends in .XCF, which is the file format for GIMP. Then choose which folder you wish to save the image in.

If you want a file type different than .XCF, you can find “Export As” in the File menu. This will allow you to export the image as a different file type, such as JPEG. Select your preferred file type and then export it to wherever you want on your computer, just like you would with any save file.

Final Thoughts

Using GIMP is really that simple. All the tools are easy to find, easy to use, and they make effective edits. Even if you’re still a little confused after reading the tutorial on how to use GIMP, rest assured that once you start editing, all the pieces will fall back into place.

If you find yourself confused later on down the road, simply refer back to this page and find the part that’s confusing you, whether it’s how to adjust the value channel or how to adjust your saturation.