First of all, let me confess that I virtually never use cross processing. But before moving on to another color topic, I wanted to take some photos and see how cross processing might enhance their look. The idea here is based on Ilan's comment that sometimes people use effects to cover up a bad photo. So the following represent three photos that I already like in their plain old unretouched versions and one photo that I never really liked until it was cross processed.
In this photo, the muted tones of the wall around the Louvre become a yellowish-green, and the contrast between the background and the man on rollerblades is strengthened. In my opinion, the cross processing works here because of the increased contrast.
I like the original of this photo because of its strong graphic nature. Here, the cross processing intensifies an already strong contrast and turns the previously green-gray walls a color of blue that works well with the sign.
The washed out background and yellowish tint—both due to cross processing—make the skater (who is about to wipe out) a more clear object of focus. If I were to make an even trendier look, I would probably use some brushes. I did, however, add a slight yellowish vignetting.
This last photo did not interest me in its original version. But here, it becomes an almost surreal study in color. My own conclusion is that cross processing could work well for stylized and very graphic pieces.