creating a B&W block print look in the compositor

Because I wanted to recreate the look of old wood block print or newspaper prints I experimented a bit in the compositor. The result is quite versatile and documented in full in this article. A sample is shown below. The real trick is to use good textures so here I used the built-in wood and marble textures but in an ideal world I could write an OSL shader to use in the compositor. This is not yet possible but at the Blender Conference I heard a rumour that this might be possible in the future.