Yesterday, I quickly produced a rubber stamp effect graphic as a banner for the Start a New Hobby Week and it made me think that this is quite a useful technique to be able to produce using a pixel-based image editor like GIMP.
As you'll see, this tutorial produces the effect of a rubber stamp on paper, but the technique can be used in many ways to produce distressed grunge effects, both for print and web.
Note: If you're a Paint.NET user, this same technique is covered in How to Make a Rubber Stamp Effect with Paint.NET. You can also find rubber stamp effect tutorials for Photoshop and Photoshop Elements.
1. Open a Blank Document
In GIMP, go to File > New... and set the image size depending on how big you need the final image to be. I set mine up at 1024x768.
2. Choose a Textured Photo
To produce the irregular and distressed final effect, we need to use a photo of some sort of textured surface, such as stone or concrete. You could take a photo specially for this purpose, but otherwise you could do a search for textures on free image sites such as stock.xchng and MorgueFile.
Note: Whenever you download any type of file from an online resource, do always check the license terms carefully to ensure that your usage complies with any restrictions.
3. Add the Texture to the Blank Document
Go to File > Open as Layers... and navigate to the texture image that you want to use and click the Open button.
4. Posterize the Texture Layer
The next step is to simplify the texture layer to a limited number of colors that we can use to to form a random selection. To do this go to Colors > Posterize and move the slider to the left. You want to produce an image that has some marked areas across the image made up of a single color. In my example, I set the slider to three and if you click the thumbnail, you should be able to see that this has given quite a lot of disparate areas of a darkish gray and it is this that I'll be using to produce a selection.
5. Add Some Text
Click on the Text Tool in the Toolbox and then click on the image to open the GIMP Text Editor dialog, into which you can type your text. When you've finished writing, click the Close button. You can change the font and the text size using the controls in the Tool Options palette below the Toolbox. I've selected Arial Heavy as this technique generally works best with bold fonts.
6. Add an Outer Border
Many text rubber stamps have a border around them and we can use the Rectangle Select Tool to add one to our stamps also.
First go to Layer > New Layer and then draw a rectangle around the text. When you're happy with the positioning of the rectangle, go to Edit > Stroke Selection and in the Stroke Selection dialog increase the Line width (I set mine to 16px) and click Stroke. Remember that you can go to Edit > Undo if the box doesn't look right and then apply the stroke again with different settings.
When the box is as desired, in the Layers palette, right click on the layer with the rectangle on it and select Merge Down. You can now go to Select > None.
7. Use the Select by Color Tool
Now you can click on the texture layer in the Layers palette to make it the active layer, as we're going to make a selection next using this layer.
You need to change to the Select by Color Tool which is represented by a blue, red and green icon. I've planned to use the dark gray color to make a selection, so I've clicked on an area in the texture layer that is colored that dark gray.
In order to make a reasonably sized selection, I increased the Threshold slider in the Tool Options palette to include more shades of gray in the selection.
8. Apply a Mask to the Text
We no longer need to see the texture layer, so go to the Layers palette and click the little Eye icon that appears next to the texture layer to make it invisible. Then right-click on the text layer and select Add Layer Mask from the context menu.
In the Add Layer Mask dialog, click on the Selection radio button and also ensure that the Invert Selection box is checked, before clicking the Add button.
While the techniques in this tutorial have been specifically aimed at producing a rubber stamp effect in GIMP, it can also be used to produce distressed grunge textures for a wide range of uses.