Image to STL: Print Reliefs and Lithophanes From Any Picture

Turning a picture into a printable 3D object is one of the most satisfying things you can do with a 3D printer. The technique is simple: every pixel's brightness becomes a height. Get a few details right and you can print signs, coasters, tactile maps and backlit photo lithophanes.

How brightness becomes height

The image is sampled onto a grid. Each grid point becomes a vertex whose height comes from the pixel's luminance. The grid is closed with a flat base and four side walls to make a solid, printable body. Three mappings are useful:

• Relief: bright pixels are high. Good for logos on a dark background.
• Inverted relief: dark pixels are high. Good for black line art on white paper, the most common case for drawings.
• Lithophane: dark pixels are thick, so less light passes through them. Lit from behind, the print shows the original photo.

Preparing the image

1. Boost contrast. A washed-out image produces a nearly flat relief. Stretch the levels so you have true blacks and whites.
2. Simplify for reliefs. Fine texture such as skin pores or paper grain becomes bumpy noise. Keep smoothing on, or blur slightly first.
3. Use transparency for logos. In a transparent PNG, empty areas sit at base height, so only the artwork is raised.
4. Crop to the final shape. The output keeps the image's aspect ratio.

Detail versus file size

Detail is the number of grid points on the long edge. At 180 points a 100 mm print has a point roughly every 0.55 mm, which is close to what a 0.4 mm nozzle can reproduce. Going to 300 increases the triangle count about 2.8×, often with little visible gain on FDM printers. Resin printers can benefit from the higher setting.

Print settings that work

Setting	Relief	Lithophane
Orientation	Flat on the bed	Standing upright
Layer height	0.12–0.2 mm	0.1–0.12 mm
Infill	15–20%	100%
Filament	Any	White PLA
Speed	Normal	Slow outer walls

Printing lithophanes upright puts the fine detail in the X/Y plane, where printers are most precise, rather than relying on layer steps. A brim helps keep a tall, thin print stable.

Scaling

Our STL exports are 100 mm wide. Scaling in the slicer scales thickness proportionally, so a 200 mm lithophane is twice as thick. If you want a larger print with the same thickness, scale only the X and Y axes.

Make one now

Upload an image on the image to STL tool, preview the relief in 3D, and download the STL. If you need a full 3D object instead of a panel, use AI image to 3D.