Lithophanes basically look like topographical maps but when they are backlit, a picture appears. They have been around for hundreds of years, but I've only recently discovered them and that they can be 3D printed. So I took a couple of photos, one of the Ghostbusters, and one of myself with Michael J Fox and converted them to lithophanes.
I learned how to do these from YouTube channel RCLifeOn.
The basic process is picking a photo and going to http://3dp.rocks/lithophane/ to have a printable lithophane file created. Make sure your Model Settings Thinnest Layer is set to 0.4mm.
And make sure your Image Settings are set to Positive Image.
I then upload my picture, choose Outer Curve as my model, run the program and download my STL file which I then send to my Slicer program.
I printed these at 0.1mm layer height with no support, 100% rectilinear infill, 1 top, 1 bottom and 1 perimeter layer, and a 5mm brim to help it stay attached to the build plate. Obviously, you can play around with these settings, but that's a good place to start. These prints took about 4-5 hours at those settings.
