GIMP 2.8: Basic color splash effect with an Alpha Channel & Eraser

GIMP 2.8: Basic color splash effect with an Alpha Channel & Eraser

In this GIMP 2.8 tutorial for beginners, we’ll look at how to create a basic color splash effect in no time. This effect consists of bringing out color in a black and white image and it can make photos look captivating, especially when colorful elements are made to stand out.

Without further ado, let’s get started.

Assets we’ll be using

To follow along without any challenge whatsoever, click on the link below and save the Pixabay stock image on your computer.

1. Preparing the image in GIMP

Step 1

The first step is to open your GIMP application and open the image saved from Pixabay by going to File > Open or hitting CTRL+O on Windows.

Step 2

Next, duplicate the layer by right-clicking it and selecting Duplicate Layer. This will create a new layer with “copy” appended to its name.

Duplicate your layer.

Step 3

You may come back to this GIMP file long after you’re done working on it, so let’s keep things organized a bit. To add clarity, rename your layers. We will be adding an alpha channel to the new layer on top, so let’s specify that with proper renaming. Right-click your top layer and select Edit Layer Attributes, then write your layer’s new name.

Editing your layer's attribute in GIMP to give it a new name.

Here I am renaming my layers to Alpha channel layer and Original photo, respectively.

2. Adding Alpha Channel

Step 1

Next up, we want to add an alpha channel for transparency. There are different ways to do that, but in this tutorial, we’re going to move to the main GIMP menu and select Layer > Transparency > Add Alpha Channel.

Add an alpha channel to your layer for transparency.

You will notice that once the alpha channel has been added, your layer’s name will no longer appear in bold font.

3. Desaturating the image

Step 1

Remove the colors of the image by using the Desaturate tool. To access it, simply go to Colors > Desaturate. Make sure the layer with the alpha channel is selected, though.

Selecting the Desaturate tool in GIMP

Step 2

Pick the Average shade of gray, and click OK.

Selecting the Average shade of gray in GIMPs Desaturate tool.

4. Creating the Color Splash Effect

Step 1

Go to Tools > Paint Tools > Eraser. GIMP’s Eraser tool, which is also accessible by hitting SHIFT+E on Windows, will allow us to eliminate parts of the top layer and display whatever is beneath it (the colored, original layer).

Using the Eraser in GIMP.

Step 2

Open the brushes dialog if it’s not already opened by selecting Windows > Dockable Dialogs > Brushes.

Opening the Brushes dialog.

Step 3

Pick the brush with Hardness 050, and set the Spacing to a minimal value, e.g. 3.

Picking the Brush with Hardness 050.

Step 4

Make sure that your tool options dialog is open by selecting Windows > Dockable Dialogs > Tool Options. Set the Size to a value of 30.00 and leave the other settings in their default state.

Tool options for brushes.

Step 5

Zoom into the image at 400% so you can better erase the parts where you want the original color to show. Red stands out in gray very well, so let’s use the Eraser on the sliding player with the helmet. If you switch back quickly to the original layer, you will realize that she is in fact the player in the red outfit.

Zooming into an image at 400 in GIMP.

Step 6

Start erasing by clicking and dragging your mouse on the chosen softball player, and pay attention to the edges. You want to be precise enough to look accurate when the image is zoomed out.

Erasing the image with an alpha channel to create a color splash effect.

Quick tip: Avoid erasing large areas in a single click. You will lose everything you’ve erased during that click if you undo or press CTRL+Z once. To lower the risks, aim for one small area at a time.

5. Adjusting the Brightness and Contrast

Once you are done with the Eraser tool, you should have an attractive image like the one below. However, we can further enhance this by adjusting the Brightness and Contrast of the original image.

Almost done creating the color splash effect.

Step 1

Click on the second layer to activate it, then go to Colors > Brightness-Contrast.

Step 2

Increase the brightness to 20 and the contrast to 10, then click OK.

Adjusting the brightness and contrast of the original image.

Later, when you become more familiar with brightness and contrast levels, you can make more sophisticated changes using the Levels tool instead; but we will not be exploring that area in this GIMP beginner tutorial.


Color splashes always work well to center a user’s attention on a subject when working with images presenting various colors. As you can see, a lot can be done with only the help of an alpha channel, the Eraser tool and brightness-contrast adjustment.

Final photo as a JPEG

I hope this GIMP 2.8 tutorial helped you grasp the basic concepts covered, and have fun creating color splash effects!