Last week I was trying to create the effect of Lomography in GIMP, at first I found several tutorials explaining how to change it from the saturation and contrast of the image (both figures led to 50% .) But I seemed very simple and cumbersome process, especially because what you are looking for a purpose. Looking
I found a script-fu called "back" and run it as a result got the picture that accompanies this post. But what is a script-fu?
PhotoShop Like when we use macros to automate functions, GIMP has the option Script-fu which is a small language with which we can develop our own scripts that can then be applied. Personally, I'd never paid attention to the Script-Fu, to be a more complex language and whenever I have needed to process for macros in GNU / Linux I used Phatch , but I discovered (because I did not know before) that there are many scripts online that you just have to download and once located in the folder "scripts" appear in the filters menu. Create a Script-fu is another different problem, but a script of these is most effective and complete a Photoshop macro writing process is much more complex and requires more experience in the program.
The Loin I used can be downloaded from this site http://registry.gimp.org/node/7870
and complete list of scripts can be downloaded from http://gimp-registry.fargonauten.de /
Where are thousands of scripts and plugins for GIMP
I've played a lot with these scripts, if you want it I've done you can go to http://fotoblog.danielmonje.com/