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Ogaday/README.md

Created February 2, 2026 20:28
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Trichrome process
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README.md

Here's my process using the free and open source image editor, GIMP (I'm using version 2.10)

  1. Launch GIMP
  2. Open your R/G/B/IR images: File > Open as layers / CTRL-ALT-O
  3. Optional: Add tags to your image layers: Right click layer > Color Tag > Choose R/G/B/Gray (IR)
  4. Set mode to grayscale: Image > Mode > Grayscale
  5. Align layers:
    • Disable layer visibility (press the eye) for each layer except the bottom one
    • For the next layer, make visible and, making sure the layer is selected, set mode > subtract.
    • Select the move tool and use your arrow keys to make sure the layer is aligned with the layer below.
    • Repeat these steps for each layer, and make all layers visible and set mode to "normal" when finished.
  6. Resize canvas: Image > Fit Canvas to Layers
  7. Resize each layer: Right click layer > Layer to image size
  8. Combine your layers into an RGB image: Colors > Components > Compose and choose which layers to use for each color channel. This will create a new file with your trichrome image, which you can crop, edit, export etc.
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