Free color lithophane maker

Your photo's brightness range is divided evenly into 2 to 8 layers, and each layer is one filament color. Layer 1 is the lowest, darkest band — put your darkest filament there and keep lighter colors above it. Each color above the first starts one layer step higher: with a 0.6 mm base and 0.4 mm steps, a four-color print changes color at 0.6 mm, 1.0 mm, 1.4 mm, and 1.8 mm. If your image reads better reversed, flip invert. The STL you download is a closed solid — a heightfield top, side walls, and a flat bottom — so your slicer accepts a printable part rather than a paper-thin surface.

Yes — your printer changes color by height, not with extra extruders, so any printer can do this. You print the first color, pause at the swap Z height, change filament by hand, and resume; that is the whole technique. If you have a Bambu AMS, Prusa MMU, or a similar system, your slicer can automate the same sequence when its profile supports material changes at Z heights. Either way, you never have to work the sequence out from the mesh yourself: the downloadable swap plan tells you which color starts at each height, so setup is copying numbers, not doing math.

Your best candidates have a clear subject, broad tonal regions, and a controlled background — a portrait, your pet, a logo with gradients, poster art, or a simple landscape silhouette. Busy pictures fight the format: heavy noise, tiny text, harsh shadows, and low-resolution screenshots break up into scattered color islands that are hard to read after slicing. Start with four layers, keep darker colors below lighter colors, and print at a modest layer height such as 0.35 to 0.45 mm. Add layers only when your photo has smooth tonal transitions and you are happy to make the extra swaps — more layers mean smoother color, but also more pauses and more careful calibration.

You get the fast version of filament painting here: a free, browser-based color lithophane STL, a live layered color preview, and swap instructions in multiple languages — with nothing uploaded. What you do not get is the deep calibration of specialist desktop tools: no TD transmission-distance material library, no measured filament opacity profiles, no blend previews for every brand, and none of the detailed painting controls advanced desktop workflows offer. If your project needs exact TD-calibrated color mixing, the original advanced desktop app workflow is the right tool. If you want to turn a phone photo into a printed gift without installing anything, this covers it.