Custom brushes are one of GIMP’s most powerful features. Many of GIMP’s essential tools are brush-based, so the ability to customize the exact shape of the brush for your needs can unlock incredible new creative possibilities. Once you understand the basic process, the sky’s the limit!
There are four different types of brush in GIMP: ordinary brushes, color brushes, image hoses (no, seriously), and parametric brushes. Ordinary brushes and color brushes are the most popularly used type of brush, so let’s look at how you can make your own in GIMP.
Brush-making Basics in GIMP
Ordinary brushes are the most commonly used brush, perfect for all kinds of painting and editing tasks. The process to make your own custom brushes only has three basic steps:
Step 1: Create or select an image as the basis of your brush.
Step 2: Switch the image mode to grayscale – RGB mode images will not work properly. Black areas will be replaced by your foreground color, white areas will be completely transparent, and grays will be partially transparent.
Step 3: Save it as a GBR file in your GIMP brushes folder.
That’s all you need to do to make your own brushes in GIMP! If you want to learn to get a bit fancy with things or just have the steps explained a bit more, read on. I’ll also explain the other types of GIMP brushes you can make, and when you might want to use them.
Bonus: Using Clipboard Brushes
One of GIMP’s handy features automatically turns anything in your clipboard into a color brush, with no input from you. If you have image data copied into your clipboard, a new brush appears in the Brushes palette, ready to be used as an image stamp.
While this is handy for a few situations, it’s not nearly as flexible as creating a brush file the longer way. GIMP also squashes your clipboard content in a 1024 pixel square, so it’s still usually a better idea to go through the long, agonizing process described below. Three whole steps! 😉
Creating Ordinary Brushes in GIMP
I’m not sure why the developers chose to call them ‘ordinary’ brushes – it almost seems insulting. They’re not ordinary, they’re actually pretty amazing. You show ‘em, little brush!
Selecting An Image
Open the image you want to use as a brush, or create a new one from scratch in GIMP. For this example, I’ve scanned a splatter on a piece of paper to use as the basis for my brush. It was absolutely, 100%, very definitely not created when I spilled my coffee this morning. Honest.
(This time I used dark soy sauce, and it was on purpose… ahem.)
When used as a brush, black areas will be replaced by your chosen foreground color, and white areas will be transparent. Gray areas will be partially transparent, depending on their grayscale value. This makes choosing a good source image essential if you want to go for fancy effects!
Prepping Your Image
Next, we’ll need to convert the image to grayscale mode. Even if your image is already grayscale, we need to actually discard all the RGB channel data. This is what makes GIMP treat it as an ‘ordinary’ brush instead of a color brush, which would ignore our foreground color choice.
Open the Image menu, select Mode, and then click Grayscale. This changes the image mode from a typical 3-channel RGB image to a single channel. GIMP can then use that as information as an alpha channel to control transparency variations within your brush.
Saving Your GIMP Brush
Open the File menu, choose Export, and then click Select File Type at the bottom of the Export window. Scroll down to select GIMP Brush with the corresponding extension GBR. Don’t save it just yet!
In order for GIMP to locate the brush file, we need to save it in GIMP’s brushes folder. The location of this folder changes a bit depending on which operating system you’re using. Here are the default pathways for your editable brushes folder:
- Windows – C:\Users\Your User Folder\AppData\Roaming\GIMP\2.10\brushes
- macOS – Users > Your User Name > Library > Application Support > GIMP > 2.10 > Brushes
- Linux – /home/Your User Name/.gimp-2.10/brushes
If you’re planning to make a lot of brushes (you might get hooked once you start using them), once you’ve navigated to this folder in the Export Image window, you can click the small + sign at the bottom of the Places pane to bookmark it for easier access later on.
Double-check that you’re saving to the right folder, and click Export. The Export Image as Brush window appears, giving you the chance to add a description and specify the default Spacing for your brush. You can always change it later on when you’re using the brush.
Spacing defines how many pixels of stroke go by before the image is ‘stamped’ again. If you want a continuous stroke of your brush, set the spacing to zero. If your spacing is set wider than the brush-width, you’ll get a repeated sequential pattern of your brush image along the stroke.
Click Export one final time, and then refresh your brushes by clicking the Refresh Brushes button at the bottom of the Brushes palette, located by default on the right of your GIMP window. If the palette is closed, open the Windows menu, select Dockable Dialogs, then click Brushes.
Creating Color Brushes
Color brushes are even easier to make since they use the exact same process as if you were making an ‘ordinary’ brush except you skip the step of making your image grayscale. You can’t control the color later on when you’re using it, but it’s great for making watermarks and stamps.
Parametric Brushes and Image Hoses
The other two types of brushes you can make with GIMP are image hoses and parametric brushes. They’re a bit more difficult to work with, and so they each deserve their own guide to properly explore all their options. If there’s enough interest, I’ll write up a post about them.
Image hoses are also known as animated brushes because they actually contain a number of different still images that are painted in sequence. If you wanted to paint autumn leaves on a tree, an image hose could automatically swap different leaf images to create a more realistic effect.
Parametric brushes are created using GIMP’s Brush Editor. While this sounds powerful, it has some benefits and tradeoffs. It’s best for creating realistic brushes that mimic real drawing and painting tools, instead of more flexible applications like splatter brushes.About Thomas Boldt