Printing lithophanes: photos that glow when backlit
are explained briefly when you hover over or tap them.
A lithophane is a thin plate whose thickness follows the brightness values of a photo. Thick areas let little light through and look dark, thin areas glow brightly. Without light behind it you can hardly see anything; with light, the picture appears. For a good result the main things are: white or very light PLA, printed completely solid (100 % infill), a fine layer height of around 0.1 mm and an even light source behind it.
How it works
The principle dates from the 19th century, when thin porcelain was used. In 3D printing, a light-coloured plastic takes over this role. The thicker the spot, the more light is absorbed or scattered. For typical lithophanes, QIDI gives a thickness range of about 0.8 to 3.2 mm. In Cura, UltiMaker recommends a relief height of 2 to 3 mm above a thin, solid base plate if the thick areas should still let a little light through.
From photo to model
1. Prepare the image
UltiMaker gives these tips:
- Convert to black and white: This shows you in advance how the result will look. Some colours look almost identical in greyscale.
- Increase the contrast: Slightly stronger contrast strengthens the effect.
- Crop: Leave out unimportant areas. Very large, detailed images take a long time in the slicer.
- Add a dark border: An even dark frame makes the part more stable, makes it easier to remove from the build plate and fits better into frames or lamps.
According to UltiMaker, portraits, animals, landscapes and ultrasound images work well.
2. Generate the model
| Tool | Type | Notable feature |
|---|---|---|
| UltiMaker Cura | built into the slicer | open the image directly, flat plate |
| ItsLitho | online | many shapes such as plate, arch, cylinder, lampshade, also coloured lithophanes |
| 3dp.rocks Lithophane | in the browser | free image-to-lithophane converter, also runs offline according to the provider |
| Lithophane Maker | online | Bambu Lab uses it in its guide for coloured lithophanes |
| Make My Lithophane from Bambu Lab | online on MakerWorld and in the Bambu mobile app | single-colour or coloured, delivers a ready-configured 3MF file for Bambu Lab printers |
In Cura you open the image like a model. In the window that opens, you set the following, according to UltiMaker:
- Height: Height of the relief above the base plate, 2 to 3 mm for lithophanes.
- Base: Thickness of the solid base plate. At least 1 to 2 layers; too many reduce contrast and light transmission.
- Darker is higher: Dark areas of the image become thicker. For lithophanes this is the right setting.
- Color model: “Translucency” is intended for lithophanes.
- Smoothing: smooths edges, but costs contrast and accuracy.
The most important settings
| Setting | Guide value | Source |
|---|---|---|
| Layer height | 0.1 to 0.12 mm | QIDI |
| First layer | 0.1 to 0.2 mm | UltiMaker |
| Infill | 100 %, alternatively top layers at least half as thick as the part | UltiMaker |
| Nozzle | 0.4 mm is decent, 0.25 mm more detail, 0.6 and 0.8 mm only for large images with little detail | UltiMaker |
| Line width | close to the nozzle diameter | UltiMaker |
| Speed | slow, 30 to 45 mm/s for plates printed upright | QIDI |
| Adhesion | brim | UltiMaker, QIDI |
| Detect thin walls | off, so the lightest, thinnest areas are not dropped | QIDI |
Why 100 % infill? Every gap on the inside is visible when backlit. QIDI describes how even small voids show through as stripes or moiré patterns. After slicing, check in the preview that no infill pattern is generated and that the layers are solid.
More on layer height is in Choosing the right layer height, more on infill in Setting up infill.
Print flat or upright?
| Orientation | Advantage | Disadvantage |
|---|---|---|
| Flat on the bed | stable, prints reliably | detail limited by the nozzle’s line width |
| Upright | detail determined by the layer height, so finer | tall, thin plate can wobble, tip over or come loose |
By default Cura lays image lithophanes flat, because according to UltiMaker that gives the best chance of success. Upright, it becomes more detailed but unstable. For plates printed upright, QIDI recommends:
- aligning the long edge parallel to the direction of movement of the print bed (Y axis),
- a large brim or small round adhesion discs at the corners,
- printing slowly so the nozzle does not drag at the plate.
How printers with a moving bed behave is explained in Bed slinger or CoreXY.
Which material?
- White or very light PLA is the standard. UltiMaker recommends white, pearl white or light grey. For single-colour lithophanes, Bambu Lab uses PLA Basic in Jade White.
- Transparent filament is not needed. According to UltiMaker it can even weaken the effect.
- Filled filaments with carbon fibre or glitter let hardly any light through, according to QIDI, and are not suitable.
Coloured lithophanes
With a multi-colour system you can also print coloured lithophanes. Bambu Lab describes a workflow with four colours: cyan, magenta, yellow and white. It recommends a 0.2 mm nozzle, a first layer of 0.15 mm, 3 top and bottom layers and 100 % infill with a rectilinear pattern. The order of the spools in the multi-colour system must match the assignment in the slicer, otherwise the colours will be wrong. The basics are in Multi-colour printing.
Lighting
- Use LEDs. QIDI points out that PLA softens at only around 55 to 60 °C. LEDs stay considerably cooler than incandescent bulbs.
- Even light: In its lithophane frames, Bambu Lab inserts flat LED panels and puts a printed light guide plate made of white PLA in between.
- Mind the heat in the housing: If it gets warm inside a closed lamp housing, QIDI advises a more heat-resistant material.
Typical problems
| Problem | Common cause | Solution |
|---|---|---|
| Stripes or patterns when backlit | infill below 100 % or vibrations with plates printed upright | infill to 100 %, print more slowly, long edge along the Y axis |
| Image too dark | relief too thick | reduce the height in the generator |
| Light areas missing or with holes | thinnest areas are left out by the slicer | switch off thin wall detection |
| Plate tips over or comes loose | tall and narrow, little contact area | brim, adhesion discs, slower |
| Image looks flat | too little contrast in the photo, base plate too thick | increase contrast, fewer base layers |
Sources
- Preparing the image, Cura settings, material, nozzle, flat orientation: UltiMaker Support: How to 3D print a 2D image with UltiMaker Cura
- Thickness range, layer height, 100 % infill, printing upright, speed, material, heat: QIDI: How Lithophanes Work
- Make My Lithophane, coloured lithophanes, Lithophane Maker, frame and light guide plate: Bambu Lab Wiki: CMYK Color Lithophane Printing Instructions
- Generators: ItsLitho, 3dp.rocks Lithophane, Lithophane Maker