How to Make a Spatter Brush in GIMP

Creating a custom spatter brush in GIMP from a scanned toothbrush ink splatter allows you to add authentic, organic textures to your digital artwork. This process involves scanning your physical splatter at a high resolution, importing it into GIMP, removing the paper background to isolate the ink droplets, and saving the result as a GIMP brush file (.gbr). Once saved to your brushes folder, the custom texture can be used dynamically with any color or brush dynamic in your digital toolkit.

Step 1: Scan and Prepare the Splatter

  1. Create your ink splatter on clean white paper using an old toothbrush dipped in black ink.
  2. Scan the artwork at a high resolution—preferably 300 to 600 DPI—to capture the micro-droplets clearly. Save the file as a lossless format such as PNG or TIFF.

Step 2: Import and Isolate the Image in GIMP

  1. Open GIMP and go to File > Open to load your scanned image.
  2. Use the Rectangle Select Tool to draw a box around the best section of the splatter pattern.
  3. Go to Image > Crop to Selection.

Step 3: Clean the Contrast

  1. Go to Colors > Desaturate > Desaturate and click OK to ensure the image is strictly grayscale.
  2. Open Colors > Levels or Colors > Curves.
  3. Adjust the white point slider toward the center to force the paper background into pure, solid white.
  4. Adjust the black point slider to make the ink droplets solid black, ensuring all stray paper texture disappears while retaining fine droplet details.

Step 4: Remove the White Background

  1. In the Layers panel, right-click the splatter layer and select Add Alpha Channel (if it is not already bold/enabled).
  2. Go to Colors > Color to Alpha.
  3. Ensure the selected color is pure white (#ffffff) and click OK. The white paper background will turn into transparent checkerboard, leaving only the black ink marks.

Step 5: Crop and Resize the Brush

  1. Go to Image > Crop to Content (or Autocrop Image) to eliminate excess transparent space around the spatter.
  2. If the splatter exceeds 2000 pixels, go to Image > Scale Image to reduce the dimensions to a manageable size, such as 1000 to 1500 pixels on its longest edge, to prevent brush lag.

Step 6: Export as a GIMP Brush

  1. Go to File > Export As...
  2. Name your file with the .gbr extension (for example, toothbrush_spatter.gbr).
  3. Set the save destination to your GIMP brushes directory:
    • Windows: C:\Users\[Username]\AppData\Roaming\GIMP\2.10\brushes
    • macOS: /Users/[Username]/Library/Application Support/GIMP/2.10/brushes
    • Linux: ~/.config/GIMP/2.10/brushes
  4. Click Export.
  5. In the export dialog that pops up, enter a descriptive brush name in the Description field and set the default Spacing (a value between 20 and 50 usually works well for spatters). Click Export.

Step 7: Load and Test Your Brush

  1. Open the Brushes dialog dock in GIMP (Windows > Dockable Dialogs > Brushes).
  2. Click the Refresh button (the circular arrow icon) at the bottom of the panel to load the new brush without restarting the program.
  3. Select the Paintbrush Tool, choose your new spatter brush, and adjust the size and dynamics to begin painting.