Working with the foreground and background color swatches in GIMP is one of the first things a new user should learn. They’re used in almost every project aside from photo editing (actually, sometimes even in photo editing), and they’re a great way to break the ice and start getting to know the GIMP interface.
Note: this article is about working with the foreground and background color swatches and using color pickers in GIMP, not about photo editing. If you want to change the color of the background in a photo or other image, you should check out this tutorial instead.
If you want to change the background color of a new GIMP document, you can specify it in the Advanced Options section of the new file dialog window.
What is Foreground and Background Color in GIMP?
The entire concept of foreground and background colors may seem a bit abstract and meaningless in modern image editors, but Photoshop first set the trend decades ago, and many other image editors still follow along.
When working with a single-layer image with no alpha channel for transparency, the foreground color is used by the Paintbrush tool, and the background color is used by the Eraser tool.
In the early days of computer graphics, that was enough for most people who wanted to create the illusion of “erasing” pixels using only a single layer.
The background color used by the Eraser tool could be matched to the image’s background color, and painting that over any other pixels in your image would make it seem like they had been erased. When the ability to actually delete pixels and leave transparent areas behind was added, the original system stayed in place.
As soon as you add an alpha channel or begin working on a second layer in your image, the Eraser stops ‘painting’ with the background color and actually removes pixels from your image to create transparent areas, which makes a lot more sense to me from a conceptual standpoint.
For many digital artists, the foreground/background system really just allows you to have two colors ready to be used at one time rather than being used by the Paintbrush/Eraser tool pairing, but palettes and other color-picking methods are usually a much better choice for storing and reusing multiple color values in a project.
The Background Color Swatch
The currently active foreground and background colors are displayed in two color swatches at the bottom of the Toolbox panel on the left side of the GIMP interface.
By default, the background color is set to white. The background color swatch also appears to be placed behind the foreground color swatch to help you identify which swatch is which.
To change the background color, click the swatch. GIMP will open the Change Background Color dialog window, which offers several different ways to select a new background color.
You can select your hue from the color spectrum column in the center of the dialog window and then specify your exact color saturation and brightness using the larger color graph on the left side.
You can also use the RGB or LCh color sliders to specify a color or even use the hexadecimal notation system used by HTML web browsers.
You can also experiment with different ways of displaying your color choices using the tabs in the upper left corner of the dialog window. Each format is just another way of displaying the same color data, so it really comes down to personal preference.
To reset the foreground and background colors to the black and white defaults, press the keyboard shortcut D.
One of the most useful aspects of the foreground/background color system helps a lot when creating a layer mask.
In a mask, white pixels are 100% opaque, black pixels are 100% transparent, and grayscale pixels are partially visible, and it’s possible to swap back and forth between painting with white pixels or black pixels using the keyboard shortcut X, which allows you to quickly refine a mask without having to switch tools.
The Color Picker Tool
You can also set the background color using the Color Picker tool to duplicate a specific color from an image or photo. This tool is known as the Eyedropper in Photoshop, and GIMP actually uses an eyedropper icon for their version, despite changing the name.
Switch to the Color Picker tool using the Toolbox panel or the keyboard shortcut O.
In the Tool Options panel, change the Pick Target option to Set background color.
Place your cursor over the area of color that you want to duplicate, and click once. The background color swatch in the Toolbox panel will update to display the new color.
A Final Word
That covers everything you need to know about how to change the background color in GIMP! Hopefully, you also learned a bit about how the foreground/background color system came about and why it’s still being used today, but that’s just icing on the cake.
Working with colors in GIMP is easy and rewarding, so start practicing your color-mixing skills right away!About Thomas Boldt