Cross processing, or "When is the wrong color the right choice?"

What is it?
Depending on your experience, you may or may not have heard of cross processing (or "xpro" if you're into abbreviations), but even if you have never picked up a camera, I guarantee you have seen the look: odd color shifts and increased contrast give an effect that is sometimes glam, sometimes "rocker," nostalgic, surreal, or even creepy.

And speaking of creepy, here are a couple of examples with a crop from I photo I took of a clown in New Orleans:


At left, you have the original photo as shot. The middle and right versions represent digitally "cross processed" equivalents of E6 to C41 (middle) and C41 to E6 (right). I put "cross processed" in quotes after digitally because cross processing proper is a darkroom technique that intentionally (perhaps accidentally in its origins?) uses the wrong chemical solution to process film. We'll get back to the analog/digital question in a minute, but first a little more on the look of cross processing.

What does it look like?
It is pretty hard to predict exactly how darkroom cross processing will change a photo, but general "recipes" exist among the darkroom crowd. My point here is not to get technical, but simply to emphasize the variety of looks that fall under the category of cross processing. If you have followed some of the links above, you have already seen some examples. But in case you didn't bother, here is a photo from my street portraiture experiment, cross-processed in four different ways:
Color and contrast shifts are the most noticeable characteristic. Realism is obviously not a priority.

How do I do it?
I won't give you a digital tutorial (much less a darkroom guide!), because there are plenty out there. Here are a few:

• This tutorial yields heavily tinted results.
• Another recipe gives a more film-like, nuanced look.
• You will start to notice the similarity in most tutorials (it's all about curves), but the style changes from one tutorial to the next, such as in this more glam example.
• I like the clarity of this simple tutorial.
• A clothing site, of all things, has a tutorial that includes a Photoshop action.
• A discussion on Flickr also includes an action.
  

Reactions (in which I lapse into Cosmo quiz results mode)
Your opinions about cross processing can reveal a lot about your own philosophy of photography. Does one of the following describe you?

• The darkroom purist: You're all about realism. You think that cross processing is a horrible mistake akin to substituting salt for flour in your favorite cake recipe.
• The analog artist: You thrive on darkroom magic—the more potions and processes the better. It's all good as long as the alchemy happens in your secluded lair with real potions. It's just not the same on a computer. Who ever heard of making magic on a laptop while sipping a latte at local Starbucks?
• The digital hipster: As long as you've seen it on MTV or in your favorite magazine, you are all about special effects. Plain old photos are fine for your parents, but if your own stuff isn't heavily tilted, tinted, and tweaked (much like your hair), then you must be having an off-day.
• The conflicted photoshopper: You appreciate both film and digital photography, but you have your own personal code of digital ethics. According to you, Photoshop versions of darkroom techniques are legit. Stray too far from analog imitation, however, and things get very uncomfortable.

I'm not sure how fair it is to reduce things to types, but I'd love to hear your own views on the matter. Personally, I think I fit the last category the best. Nevertheless, having done a lot of research on nostalgia, I am wary of clinging to the past (i.e. replicating darkroom techniques only) for its own sake. I admire thoughtful and meaningful exploration of digital imaging—the key words being thoughtful and meaningful. Something that always bothers me is a photo that seems oblivious to its own message (or that says nothing at all). Example (To be nice, I will avoid linking to any one photographer): In the world of wedding photography there is a pose making the rounds in which the young couple stands side-by-side about three feet apart, facing forward, holding hands (arms extended to the side) in perfect symmetry, stiff as boards, with expressions as solemn as the old couple in Grant Wood's "American Gothic." What exactly is that photo saying about their marriage (or marriage in general)? From a purely aesthetic point of view, the composition is interesting. But what is it saying? That the couple already views their marriage with a sort of doomed resignation? That they are bound together, but actually far apart? What kind of cynical, jaded photographer decided that would be a good pose?

But I digress (sorry, had to vent about something, since I'm writing this post from the hotel room where my family is staying after our house flooded two days ago)...

...I guess what I am trying to say is that in my opinion, any photographic manipulation is valid as long as it expresses what the photographer wants to say. However, I also accept that these matters are extremely subjective, so what do you think? Do you intentionally manipulate the color of your photos? What techniques have you tried? What limits, if any, do you set on you set on processing manipulation, and do your preferences change with digital work? Comments?