This plugin changes the color temperature of an image via shifting it in the YUV color space:
Compile and install it with:
$ CC="g++ -O2" gimptool-2.0 --install elsamuko-temperature.c
Menu entry is Colors -> Color temperature.
Windows binaries from François or Sylvie:
Mac binaries (for the macports GIMP):
Example of a warm setting with lowered exposure:
The YUV color space with the shift, the plugin does:
If you like this, hug someone.