This script simulates a photochrom image, a lithographic printing process from the 1890's:
The script is a translation of this how-to for PSE with some improvements:
Copy it into the scripts folder from GIMP, you will find it then under Filters -> Artistic -> Photochrom.
If you like it, hug someone.
An example can be found here:
Update1: Slightly different contrast layers. New retro option which replaces the orange with a yellowish color. It's recommended to switch layers on for further edits (ctrl-L). Example here:
Update2: Optional b/w dodging. It also deactivates the extra color layer. Thx to Francois for the tip:
Update3: Added a batch version of this script, run it with
gimp -i -b '(elsamuko-photochrom-batch "picture.jpg" (list 255 128 0) (list 255 68 112) 60 60 0 100 FALSE FALSE)' -b '(gimp-quit 0)'
or for more than one picture
gimp -i -b '(elsamuko-photochrom-batch "*.jpg" (list 255 128 0) (list 255 68 112) 60 60 0 100 FALSE FALSE)' -b '(gimp-quit 0)'
Be careful, the batch script overwrites the original image. More info here:
For all scripts together, go here: