How to Change Gamut Warning Color in GIMP

Soft-proofing in GIMP allows creators to simulate how an image will appear when printed or rendered in a specific color space, helping prevent unexpected color shifts. This guide explains how to configure the gamut warning highlight color in GIMP so you can easily detect and adjust out-of-gamut pixels before exporting or printing your artwork.

Configuring the Gamut Warning Color

By default, GIMP indicates out-of-gamut pixels using a specific color, but you can customize this highlight to ensure it contrasts clearly against the primary colors in your image.

  1. Open GIMP.
  2. Navigate to the top menu and select Edit > Preferences (on macOS, go to GIMP > Preferences).
  3. In the Preferences window, select the Color Management tab from the left-hand sidebar.
  4. Scroll to the Soft-proofing section.
  5. Locate the setting labeled Out-of-gamut color.
  6. Click the color swatch next to the option to open the color picker.
  7. Choose a high-contrast color—such as bright neon green, magenta, or cyan—that does not appear frequently in your composition.
  8. Click OK in the color picker, and then click OK in the Preferences dialog to save your settings.

Activating Gamut Warnings on the Canvas

Once your warning color is configured, you must enable soft-proofing and the gamut check on your active image view:

  1. Ensure you have the correct simulation profile selected by going to Image > Color Management > Soft-Proofing Profile and assigning the target ICC profile (such as a specific CMYK printer profile).
  2. Go to the menu bar and select View > Color Management > Soft-Proofing to preview the target profile.
  3. Select View > Color Management > Mark Out of Gamut Colors (or press the corresponding shortcut if configured).

Any colors in your image that cannot be accurately reproduced by the target profile will now be highlighted in the custom color you chose.

Resolving Out-of-Gamut Pixels

When pixels are flagged:

  • Use tools like Hue-Saturation or Curves on the affected areas.
  • Lower the saturation or adjust the luminance of the problem color channel until the highlight disappears.
  • Toggle soft-proofing off and on to ensure the adjustments maintain the visual appeal of the overall image while remaining within printable limits.