Probably being inspired by the early Chinese Ming vases, the Europeans started to produce pictures in translucent porcelain. These could only be viewed clearly when lit from the back.
The word itself comes from a combination of two Greek words ‘lithos’ meaning stone or rock and ‘ phainen’ meaning to cause to appear or to appear suddenly. So lithophanes are either ‘ light in stone’ or ‘ appear in stone’.
They were first introduced to the European market in the 1820’s.
These ‘magical’ pictures were very difficult to make. First an artist would work on a wax coated piece of glass, producing the image with a light behind it or in front of a window. Being back lit he could ‘see’ the finished result. Taking the wax down to a very thin layer would let a lot of light through and leaving the wax thick would produce dark areas.
From these very delicate wax castings a mould was taken, made from plaster. The wax was melted out of the mould leaving a cavity for the porcelain to be forced into every crack and crevice.
The porcelain was very carefully removed.
Then it was baked in an oven at very high temperatures, about 1400C ( 2500F).
The failure rate of these very delicate structures was very high, about 60%, partly due to the different thickness of material and partly due to the delicateness of the finished product. They were very expensive and due to this and the difficulty of manufacture their popularity died out.
They were hung in windows, used as firescreens, where the flickering light would almost cause the picture to come alive. They were used as candleshields, with the flickering light of the candles causing the pictures to dance.
Fast forward
With the advent of modern machinery, there has been a change in the way these wonderful artworks can be produced.
The computer numerical controlled machines has now allowed these pictures to be created at the flick of a switch. All of the work is carried out on the computer.
The artwork is reversed into it’s negative, changed into a height map.
This was then carved out of a solid piece of material, the limiting factor the size of the cutter used in the CNC machine.
Right up to date.
The CNC produced very good results, very quickly and with failures being able to be reworked quickly.
But then came the 3d printer.
This marvellous machine which lays a plastic thread down to build up objects is ideal for this task.
Now a print head is guided by a computer generated code to place the plastic thread (extruded filament) onto a flat build platform. This is built up in layers, producing a 3d structure.
Known as additive manufacturing or FFF ( fused filament
fabrication) this process is capable of producing very thin layers (typically 0.3mm thick).
Detail within the picture can be reproduced accurately and very quickly.
The prints can be produced flat onto the bed or they can be produced upright.
So now a curved print or even a cylindrical print is no problem even to the most basic 3d printer.
The only limitation is the print volume of the printer.
With the advent of led lighting, as naked flames and heat could cause a slight problem with the plastic material, these wonders can now be produced very quickly and easily.
How do you…
From taking the digital picture and then processing it.
One website you can upload photos to and then create a file to print out is here
Navigate to ‘image settings’ at the top
Set the image to positive
Then navigate to ‘ model settings’
Make sure you are
happy with the maximum size – you can always scale it down in the slicer program.
I tend to set the thinnest layer to 0.4mm – lets more light through – just check your nozzle size is greater than the thinnest layer otherwise it will print nothing.
Going back to the image tab you can load your image – some work
better than others , make sure there is plenty of contrast in your picture, these work better.
After loading the site should show you the model tab, you can zoom in and rotate the model with your cursor in the area of the
model.
Download the model stl file.
Use your favorite slicer program to slice it for your printer, and print.
The settings for this are 100% fill, I tend to stand it upright and add a brim( 20 lines). I have started to knock the fan speed down a little to
100 instead of 255, this helps with layer to layer adhesion and results in a less steppy model. The downside of this is that you will reduce the bridging distance.
