It’s a bit retro and possibly cheesy but I like the graphic feel of dot and line screened images creating a halftone.
Screening a photo is the process of reducing the resolution of an image into printable pixels or dots.
http://en.wikipedia.org/wiki/Halftone Newspapers and magazines use a fine screen to print a series of colors onto a page. In my case I chose to screen only a luma value image. You can vary the contrast and the size of the dots. In my case I also created 3 types of screen.
-Line at 45degrees
Heres is a screeney of my setup with results:
Dot Screen.blend (506 KB)
And here is a break down of the more elaborate version!