Using GIMP's Filter Pack it's easy to change someone's eye color to almost anything you like. In this exercise you'll change the girl's green eyes to a bright blue.
- Use the Free Select Tool
- Subtract from/add to the current selection
- Use the Filter Pack
Download the original image I used from stock.xchng
Zoom in to the girl's right eye. Using the Free Select Tool (Lasso) select the outer perimeter of the iris.
IMPORTANT: In the Toolbox, click on the Subtract from the current selection icon.
Again, using the Free Select Tool, draw a selection around the pupil. This cuts that region out of the selection. Feather the selection by 1 or 2 pixels, Select > Feather...
The selected region should only be the colored iris.
Now use the Filter Pack to modify the color of the iris, Colors > Filter Pack… You'll see the original selection and the modified selection which, at this time, are the same. Check Hue under Windows.
The Hue Variations window opens showing six possible changes to the iris. Click on Blue.
The Hue Variations window now shows six new possible hues for the iris. Choose the Cyan variation.
This is the color you're looking for, so click OK in the Filter Pack Simulation window to see the new eye color applied in the image.
I've only modified one eye for illustration purposes. You would obviously want to apply this method to both eyes. Use the Add to/Subtract from the current selection options to select the irises of both eyes.
The Filter Pack can be a fun tool with which to play and experiment. You can use it to alter the color of anything without affecting the light and shadows.