How to make a lithophane: thickness, size, light and print settings

Print settings checked on 1 October 2026 against Bambu Lab's and Prusa's own lithophane guides, linked below. Where the two makers disagree, both views are given.

To make a lithophane, turn a photo into a thin plate whose thickness follows the picture: thin where the photo is bright, thick where it is dark. Start from a sharp, well-lit photo, set the thinnest point around 0.8 mm and the thickest around 3 mm, choose the print width, and export an STL. Print it in white PLA at 100% infill with fine layers, then hold it against a light. The lithophane maker turns a photo into an STL with a backlit preview, so you can judge contrast before you spend two hours printing.

How a lithophane works

White PLA lets some light through and absorbs the rest, and each extra millimetre absorbs more. Seen from the front with a lamp behind it, a thin area glows and a thick area looks dark. The plate is nearly featureless in daylight and only shows the picture when lit from behind, which is the whole effect.

Light does not fade in a straight line through plastic; it falls off exponentially. That is why the Omnvert tool, by default, maps brightness to thickness along a light-transmission curve rather than a straight line. It assumes white PLA passes about 50% of the light per millimetre, and you can change that figure under Advanced.

Choosing the photo

• Sharp and well lit. Blur and noise become bumps in the plastic. A clear face or object with a simple background works best.
• Real contrast. A photo that is grey all over prints as a grey plate. Some separation between light and dark areas is what the light shows.
• Enough pixels. At the Standard detail setting the tool places one pixel every 0.12 mm, so a 120 mm wide print uses a 1,000 pixel wide grid. Most phone photos have far more than that.
• A format the browser can read. JPG, PNG and WEBP work. HEIC photos from an iPhone have to be exported as JPEG first.
• Cropped beforehand. The tool uses the whole photo and the height follows its proportions. Cropping close to the subject gives it more millimetres at the same print width; an empty sky or wall is plastic and print time too.

How to make the lithophane, step by step

1. Upload the photo. Files up to 40 MB are accepted, and the photo is turned into a grey grid in your browser before anything is sent.
2. Set the print width. Presets are 80, 100, 120, 150 and 200 mm; the height follows the photo's proportions. 100 to 150 mm is a common size for a desk lamp or window piece.
3. Choose the shape. Flat for a frame or a window, Curved for a self-standing piece (the arc is adjustable from 30° to 300°), or Cylinder for a lamp shade.
4. Set the thickness. The defaults are 0.8 mm for the brightest point and 3.0 mm for the darkest. Going thinner than about 0.8 mm makes the bright areas fragile; going thicker than 3 mm darkens the whole picture with a weak lamp.
5. Adjust tone if needed. Brightness, contrast and gamma sliders work on the photo before it becomes thickness. A 3 mm frame adds a solid border that makes the plate stiffer. Negative makes dark areas thin; leave it off unless you want that effect.
6. Check the backlit preview, then generate the STL. The result shows the file size, triangle count, size in mm and thickness range. Flat areas get fewer triangles, so the file stays smaller than a full grid; if it is still too heavy to share, our guide to reducing STL file size explains the options.

When the preview looks right, generate the lithophane STL and take it to your slicer with the settings below. To see how much filament it will use, drop the STL into the STL analyzer; at 100% infill the solid weight it reports is the estimate. Our guide to STL volume, weight and cost explains the numbers.

Print settings

Sources: Bambu Lab's lithophane printing instructions and its lithophane kit page, and two Prusa articles, the picture to 3D model guide and the 2024 colour lithophane article.

Standing up or lying flat

This is where advice splits. The Omnvert tool's result card suggests printing the plate standing up. Prusa's guide prints it flat to avoid the wobble a tall, thin plate can have. Both work; they trade different things.

Standing up, each layer is a horizontal slice of the picture and the thickness comes from the nozzle's XY movement, which is finer than a layer. It needs a brim, a steady printer and slower speeds. Flat, the thickness is stacked in layers, so 0.1 mm layers give 22 steps between 0.8 and 3.0 mm; it is quicker and very stable, and with fine layers the steps are hard to see. If your printer wobbles on tall parts, print flat. If you do print upright, stand a landscape plate on its long edge: a 120 × 90 mm lithophane then rises 90 mm instead of 120, wobbles less and finishes sooner.

Lighting it

A neutral or warm white LED behind the plate, a few centimetres away, shows the most detail. A bare bulb too close makes a bright spot; a diffuser or a little distance spreads it. The cylinder shape is made for a lamp: a small LED puck or string inside does the job; keep hot bulbs away, because PLA softens at low temperatures. The preview's Lamp and Warm light switches show roughly what each looks like.

Limits

The preview is a simulation for white PLA; a different filament, a thicker wall or a weak lamp changes the result, which is why a small test print at the final settings is worth it. The tool works from brightness only, so colour photos become grey lithophanes; full-colour lithophanes need a multi-filament printer and a different workflow. If the result card ever reports open edges, run the file through STL Repair before slicing. For the image side of the job, the tutorial on preparing a height map covers contrast and smoothing in more depth, and image to STL is the tool for logos and flat relief instead of photos.