Create a Contaminated Effect in GIMP

Transforming a clean graphic into a vision of decay and contamination can add a dramatic effect to your digital artwork. GIMP, the free and open-source image editor, presents an array of tools that can be used to create this unique effect. From discoloration and texturing to incorporating realistic smoke elements, you will learn to master the art of the digital decay.

Start With the Basics

Before diving into the details of creating a contaminated effect, ensure you have a good understanding of GIMP’s interface and its basic tools. Familiarize yourself with the layers panel, brushes, and selection tools, as these will be fundamental in the creation process.

Contaminated Nuke Sign Effect

One of the most iconic images associated with contamination is the nuke or radioactive danger symbol. This image requires distinct discoloration and texturing to convey the idea of radioactive decay. To achieve this effect:

  1. Open GIMP and create or import the symbol you wish to alter.
  2. Use the selection tools to isolate the area you want to contaminate.
  3. Employ various brushes to add a rusty or corroded texture. Experiment with layer blending modes to achieve different intensities and effects.
  4. Add greens, yellows, and rust colors to create a discolored, contaminated look.

Adding Smoke and Fog

Smoke and fog can simulate the vaporous elements of contamination, and GIMP provides multiple ways to add these effects:

  • Built-in Fog/Smoke Filter:
    1. Navigate to the Filters menu.
    2. Go to the Decor submenu and select “Fog.”
    3. Adjust the color and opacity to simulate a contaminated atmosphere.
  • Custom Smoke Brushes:
    1. Find and download smoke brushes compatible with GIMP.
    2. Install the brushes by placing them in the designated GIMP brushes folder.
    3. Access the new brushes and paint the smoke effects onto a new layer above your image.

Custom brushes often provide a more natural and realistic appearance, as they can be rotated, resized, and modified to fit your specific scene.

Distressing with Textures

Adding a distressed look to surfaces within your image can give a sense of age and decay:

  1. Import a texture that resembles rust, peeling paint, or general wear and tear.
  2. Place the texture over the area you wish to distress.
  3. Use layer masks to blend the texture with your original image, erasing or reducing opacity as needed.

Final Touches

For a comprehensive contaminated effect, consider integrating multiple techniques:

  • Utilize overlay techniques to blend multiple textured layers for added depth and realism.
  • Employ the pen tool to make precise selections and refinements.
  • Imbibe your project with stock images of textures or elements that sell the contaminated image, such as warning signs or hazardous materials.



Warning! contamination ahead. suite up and get ready for an awesome effect tutorial 🙂
In this tutorial we will use various overlay techniques, the pen tool and how to use stock images to add texture to the design.

Getting started.

In this GIMP tutorial i used two elements. the nuclear sign and the watercolor background so go ahead and download them from the following links.

Nuclear sign: i can’t remember where i got this freebie icon so I’ve placed it on our sever for download
Water color texture can be downloaded from Go Media’s free Watercolor Pack sampler, download

Step 1

Create a 600×450 image. if your going to use it as a wallpaper i suggest you create something bigger.

Step 2

Fill the background with black and place our nuke sign in the centre of the canvas.

Step 3

Now right click on the nuke icon layer and click on Alpha to Selection, then go to Filters>Light and shadows>Drop shadows, set the settings to Offset X:0, Offset Y:0, Blur radius:380, color a5ef17, Opacity 100 , and un-tick “Allow resizing”.

De-select selection by going to Select>None . this is how it should look

Step 4

Now Repeat step 3 but this time set the blur radius to 100.

Step 5

Next open mdp-watercolour60.jpg from the zip file you downloaded off go media and open it in gimp, then resize it to 700×990 by going to Image>Scale image.

Step 6

Next change the image to black&white by going to colors>Desaturate. then go to colors> Brightness and contrast
and set Brightness to -80 and contrast to 118.

Step 7

Now insert the watercolour image above all the other layers and then rotate the image on an angle of 128 and set the layer mode to Overlay.

Step 8

Next turn off the textured watercolor layer by clicking on the eye icon in the layer dialog this is so it doesn’t get in our way.

Step 9

Next grab the Path tool and create a curved path. the idea is to start all paths from the edge of the icon, as if its coming from behind it.

Step 10

Create a new layer. change your foreground color to yellow fdf23c and with the path still active go to Edit>Stroke path and set the value to 3px.
note* if your path disappears go to the paths dialog and right click>path tool.

This is how it should look

Step 11

Select the easer tool, erase part of the overlapping line so that it looks like its coming from behind the icon. then use the Circle fuzzy (19) easer brush to get a faded effect for the end points.

Step 12

Next will add a glow to our stroke by going to the path dialog then “right click to > Path tool” on the path we previously drew.
then select Circle Fuzzy (17) from the brushes dialog and go to Edit>Stroke Path and select “Stroke with paint tool. finally set the layer to overlay.

Step 13

As we did in step 11 use the Eraser tool to clean up the stroke ends.

Step 14

Create three more strokes each on there own layer with each layer’s opacity set to 39.

Step 15

Using the same technique as the glow strokes in step 12, will create some particle effects on two of the paths.

Create a new layer, Go to the path dialog then “right click> Path tool” on the path we previously created. Then select Sparks from the brushes tab and go to Edit>Stroke Path and select “Stroke with paint tool. repeat this to the top left stroke and when your done set layer mode to Overlay.

Step 15

We could stop here but i think this adds a nice touch to it 🙂 with the “spark brush” randomly apply some here and there, not so much though.

Step 16

Re-activate the watercolour texture layer by clicking on he eye icon and set its Opacity to 85. and thats it 🙂

The gimp XCF source file is attached below as always. enjoy!

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