How to Simulate Infrared Photography in GIMP

Simulating infrared photography in GIMP allows you to recreate the surreal "Wood effect"—where green foliage turns a glowing snowy white and clear blue skies turn dark and dramatic. This step-by-step guide explains how to use GIMP's Channel Mixer, Curves, and blur filters to transform a standard digital color landscape into a realistic black-and-white infrared simulation.

1. Select the Right Image

Choose a high-contrast landscape photograph that features abundant green foliage, vegetation, and a clear blue sky. The infrared effect relies on manipulating green and blue color channels, making greenery and open skies the most effective subjects.

2. Duplicate the Base Layer

Open your image in GIMP. In the Layers dialog on the right, right-click your background layer and select Duplicate Layer (or press Ctrl + Shift + D). Rename this layer to "IR Base" to keep your original photograph untouched.

3. Use the Channel Mixer

With the "IR Base" layer selected, go to the top menu and select Colors > Components > Channel Mixer.

  1. Check the Monochrome box at the bottom of the dialog.
  2. Set the Red channel to +100%.
  3. Set the Green channel to +100% to +150% (this drastically brightens the foliage).
  4. Set the Blue channel to -50% to -100% (this darkens the blue sky and water).
  5. Click OK to apply the channel values.

4. Enhance the Infrared Glow (Wood Effect)

Infrared film naturally creates a soft, ethereal glow around highlights known as the Wood effect.

  1. Duplicate the "IR Base" layer and name the new layer "IR Glow".
  2. Go to Filters > Blur > Gaussian Blur...
  3. Set both the Size X and Size Y to around 15 to 30 pixels (depending on your image resolution) and click OK.
  4. Change the Mode of the "IR Glow" layer from Normal to Screen or Soft Light.
  5. Lower the layer Opacity to between 30% and 50% until the highlight bloom looks natural.

5. Adjust Tone and Contrast

To give the image the deep contrast typical of infrared film:

  1. Right-click the top layer and select New from Visible.
  2. Go to Colors > Curves...
  3. Create a subtle S-curve by dragging the lower-left section down slightly to deepen the dark skies, and dragging the upper-right section up to make the foliage glow brightly.
  4. Click OK.

6. Export the Final Image

Go to File > Export As..., choose your preferred format (such as JPEG or PNG), and save your completed infrared simulation.