Filtering 2d Images

So I'm attempting to achieve so pretty visual effects in a 2d game. By running it through some filters. I researched convolution techniques and figured out how to achieve some of what I wanted to achieve. Now I'm trying to figure out how to make some kind of watercolor type effect occur. I'm looking at the photoshop watercolor filter for reference, and I'm having a hard time trying to figure out how they do it. Any help?

I should add that I don't think the photoshop watercolor filter is using a convolution matrix. It seems like they're doing a couple of separate things. But I might just be overlooking something.

http://scholar.google.ru/scholar?q=watercolor

Google Scholar. Didn't even know that existed. Thanks.

/prog/ will be spammed continuously until further notice. we apologize for any inconvenience this may cause.