A Lithophane is a peice of translucent material into which is carved a 3d image. The deeper the carving (or machining), the thinner the material and more light gets through.
The same lithophane with no light passing through.
With careful selection, the images used can look good when not lit as well, lighter background and darker main features let it ‘pop’ out in 3d.
In this case they are in wooden frames, backlit by a panel of 360leds each.
This powered lightbox style brings out the detail just as much as sunlight, but in a slightly warmer tone.
The lithophanes were machined on my CNC mill, using a 0.5mm stepover and 2mm diameter ball end mill, running at 600mm/minute it takes a while. The material is soft enough, and cuts cool enough that almost no supervision is required.