How to make a grunge brush – Gimp

Simple brushes without angle jitter

1. As before, create a grungy inkblot image -but this time, create it with a transparent background (images 1).
2. Save this as a .gbr file (the Gimp brush format), and place it in the gimp brushes directory (http://docs.gimp.org/en/gimp-using-brushes.html)
3. Re-open Gimp and your brush should be there. Throw in jitter (click Apply Jitter) and random colour variation using the Brush Dynamics setting in the brush dialog (above Apply Jitter) and you’re good to go.

Brushes with angle jitter

For this we need to have a brush that has many copies of the brush image with different rotations. To do this, I’m deferring to the excellent tool by +Rob Antonishen here.

• Download the setup-brush.scm plugin, and check out this page for how to install Gimp plugins.
• Create your brush splatter image as before, but this time make sure it’s:
  • square, so make sure the canvas has equal dimensions on each side
  • on a white background, not as a transparent png
  • flattened. Make sure there’s only one layer
• Run the brush maker script from Script-fu->Setup Rotating Brush

You’ll now have a new image with lots of rotated images in it.

• Save this as a .gih file – and make sure you follow Rob’s screenshot for the correct settings for the Save Dialog
• Move the .gih brush your brushes directory.
• Refresh the brush list – it should now be there!

My version of the grungy brush for Gimp is here if you want to download it. It’s free for any personal or commercial use – just don’t sell the brush itself.