Amanda Ghassaei, assistant tech editor at Instructables, has shown how photographs can be printed on a 3D printer giving them a relief appearance.
After demonstrating how to 3D print LP records last year Amanda used the ModelBuilder library by Marius Watz to computationally create the 3D models from the original photographs. The algorithm assigns a depth to each pixel in an image based on how dark it is. This does limit the process to greyscale images, with the darkness loosely interpreted as an indication of shadow.
The library allows the 3D model to be saved as an .STL file which is compatible with most 3D printers. An Objet Connex 500 3D printer was used to create the relief shown in the photos using a rigid, semi-transparent white material. The material is printed with a greater thickness in the darker areas of an image, such as the areas of shadow.
“By varying the thickness of a region of this semitransparent print you can control the amount of light that is able to pass through, thereby controlling the brightness (thinner regions of material will appear brighter and thicker regions darker).” explains Ghassaei.
When the print is backlit with a diffuse light, it shows the original image with subtle 3D effect where none existed in the original image.
If you want to have a go yourself you can find instructions on Instructables here.