According to Wikipedia Cross processing (sometimes abbreviated to Xpro) is the procedure of deliberately processing photographic film in a chemical solution intended for a different type of film.
This normally means taking slidefilm (E-6) film and developing it as if it was regular negative film. This results in shifted colors and stronger contrast.
So why would any sane person do this?
1) It’s fun and unpredictable. You never truly know what you will get. Especially if you throw expired film into the mix
2) Developing as slidefilm is more expensive, so its actually cheaper to develop as slide film is you are able to find a lab
The following photo’s were taken with my Holga and Kodak Ektachrome E100S. This was then crossprocessed and scanned to show the sprockets. And the results are uh, well uh, green. Kermit-the-frog-exploded-in-my-camera-green. In my past experience the green shift has never been this strong with Ektachrome, but in this case it went all the way.
On the left is hotel I stay at for business in New Jersey and on the right is an abandoned housing complex in Singapore now used by the military for practice urban warfare.
Flying over Chicago after the midwest.