Lithophane Maker: Photo to STL

A lithophane is a thin plate whose thickness follows a photo: thin where the picture is bright, thick where it is dark. Held against a window or lit from behind, the plate shows the photo in soft grey tones. This tool builds that plate from any JPG, PNG or WEBP. Pick the width in millimetres, the thinnest and thickest points, and a frame; the preview shows the result as it would look in front of a lamp, and the STL you download is a closed solid ready for the slicer.

Brightness is mapped to thickness with the physics of light through plastic, not a straight line. Light passing through white PLA fades exponentially with thickness (Beer–Lambert), so a linear ramp gives washed-out mid-tones; here the transmittance of one millimetre of filament (about 50% for white PLA) sets the curve, and you can change it after printing the calibration strip in the guide below. Brightness, contrast and gamma are adjusted on the photo itself, and a negative mode inverts the mapping for prints lit from the front.

Shapes: flat plates for frames and windows; curved plates with any arc from 30° to 300°, which stand on their own; and a full cylinder for lamps and tea-light shades, with the relief on the outside or inside. Bending preserves arc length, so the picture is never squeezed. The frame is a flat rim at the thickest setting; leave it at 0 for a cylinder that meets edge to edge.

Lithophanes are heavy meshes: a 150 × 100 mm plate sampled at 0.1 mm is three million triangles as a plain grid. This tool triangulates the relief adaptively, so flat sky and skin keep few triangles while eyes and hair keep all of theirs, with a guaranteed maximum deviation of 0.05 mm (0.02 mm on Fine) from the photo, below what a 0.4 mm nozzle can resolve. Typical files come out three to ten times smaller than grid-based generators. The photo is resampled in your browser; only the grayscale grid at the print's resolution is sent to our server, where the STL is built and deleted after the download. One lithophane a day is free; a credit pack, a 24-hour pass or a subscription covers the rest, shared with the STL Compressor and the other 3D tools.