Do it with the GIMPLUT (Look-Up Tables Effects)Gamma CorrectionDemonstration

3.2.2. Demonstration

Demo

  1. Open the A-Little-Exercise-3.jpg image.
  2. Run <Image> Layer Colors "Levels..." .
  3. Raise the value of the middle input box of "Input", and show the difference.
  4. Try to set the brightness/contrast on the original image and see that it doesn't work well.

Written by Shlomi Fish