As a testiment to actually making things from our own little hackerspace I thought I’d post about this
The idea for a paper version of a lithophane was inspired by a conversation with one of the other NortHACKton members, Max. By building up several layers of paper it is possible to create different shades of colour when they are held up to the light. Cutting away regions within a layer you can create entire pictures using this method. I wrote a quick hack of an app that converts an image to greyscale and allows you to set the thresholds for each layer. You can then save each layer as a seperate image ready for printing.
Full details and more images are available through the instructable I wrote about it, http://www.instructables.com/id/How-to-Make-a-Paper-Lithophane/