ridersofnorth

I visited the site couple of days back. Seems like they've revamped this section. Looks better. Looking forward to more content.

The first reply in that post tells that - "Essentially every image is nothing but a matrix of numbers, right? Numbers in the matrix can denote several things. For B/W image, these can be grey scale numbers from 1 to 255 (1 being the White and 255 being the Black). For colored images, each entry in the matrix can be a vector of (Red, Blue, Green) scales, since every color can be represented by these three basic colors.

Now, when you want to produce any effect, essentially you need to do some operation on this matrix. For example, if you want to remove the high contrast (sudden change of color from white to black), then you need to remove the high frequency components from your matrix. Taking a Fourier transform and removing the high frequency components and taking back the inverse transform can do the trick for you. I'm not sure about Sepia effect in particular, but all I want to convey here is doing some operation on Matrix does the job. Hope it helps."

This looks really promising. Can't wait to try it out. This will be just available on Mac?

I think these guys - http://functionspace.org have some kind of subject groups and articles. They announced some upcoming courses a little while back, perhaps they're on this idea.