Peter mentions wanting to correct the color temperature of his snow photos, which came out blue.
The best way to do this is by using the Grey Point plugin for the Gimp. (Last time I installed this it was a little out of date, but the error messages explained how to update the API calls).
Once that’s installed, this is what you do:
- Pick a color that should be white in the image (in this case, snow)
- Copy that color to the background
- Doubleclick the background color to open up the Change Background Color dialog box
- Click the “S” radio box (for saturation)
- Reduce the saturation to near zero, but not quite all the way
- Close the box
- Do Script-fu / Grey Point, and use the Background option
I find this script gets much better results than the grey point item in the levels tool:
Levels tool (note blown-out areas)
Grey point script