How to Convert Images for 3D Printing Lithophanes
3D printing lithophanes turn ordinary photographs into stunning translucent prints that reveal the image when backlit. The process maps image brightness to print thickness: light areas are thin (letting light through) and dark areas are thick (blocking light). Getting the right image format and processing is essential for a quality lithophane.
This guide covers how to prepare images for lithophane printing, including format conversion, grayscale processing, and resolution requirements for different print sizes.
Step-by-Step Instructions
- Choose a high-contrast photograph
Lithophanes work best with images that have strong contrast and clear subjects. Portraits, landscapes with defined foreground/background, and close-up shots produce the best results. Avoid low-contrast images, heavily filtered photos, or images with lots of fine detail that gets lost at print resolution.
- Convert to PNG format
Most lithophane generation software (LithoMaker, ItsLitho, 3DP Rocks) accepts PNG and JPG. PNG is preferred because it preserves full image data without compression artifacts. Open imageconvert.co and convert your source image (HEIC from phone, WebP from web, etc.) to PNG. Use maximum quality.
- Adjust image resolution
For lithophane printing, you need enough pixels for the print size but not excessive resolution. A good target is 1-2 pixels per 0.1mm of print width. For a 100mm wide lithophane, 1000-2000 pixels wide is ideal. Higher resolution does not improve the print since FDM printers cannot resolve details finer than their nozzle diameter (typically 0.4mm).
- Generate the lithophane model
Upload your converted PNG to a lithophane generator. ItsLitho.com and 3DP Rocks are popular free online tools. Configure the print dimensions, thickness range (typically 0.8mm to 3.2mm), and orientation (flat or curved). Download the generated STL file.
- Slice and print
Import the STL into your slicer software (Cura, PrusaSlicer). Use white or light-colored filament (PLA works best). Print at the slowest speed your patience allows: 20-30mm/s gives the best detail. Use 100% infill for consistent light transmission. The print should be viewed with a light source behind it.
Why Image Quality Matters for Lithophanes
Unlike screen viewing where compression artifacts are barely visible, lithophanes amplify image quality issues. JPG compression artifacts translate to inconsistent thickness variations in the print, creating visible banding and noise when backlit. This is why lossless PNG is the preferred format for lithophane source images.
If your only source is a compressed JPG, it can still produce a decent lithophane. But starting from a lossless source like PNG or converting from HEIC at maximum quality gives noticeably better results in the final print.
Texture Maps for 3D Printed Objects
Beyond lithophanes, 3D printing also uses images as texture maps for full-color prints on multi-material printers. Texture maps need to be in PNG or JPG format, UV-mapped to the 3D model's surface. For texture maps, resolution should match the print resolution of the printer, typically 300 DPI at the physical print size.
If your texture images are in formats not supported by your 3D modeling software (WebP, HEIC, AVIF), convert them to PNG for lossless quality or JPG for photographs.
Tips for Better Lithophanes
A few preparation tips can dramatically improve your lithophane results.
- Convert to grayscale before generating the lithophane for more predictable thickness mapping
- Increase contrast slightly since lithophanes tend to lose contrast compared to screen viewing
- Mirror the image horizontally if printing a flat lithophane to be viewed from the back (light side)
- Crop tightly around the subject to maximize detail in the printed area
- Avoid images with large areas of uniform brightness since they produce flat, uninteresting lithophanes
Frequently Asked Questions
What image format is best for lithophanes?
PNG is the best format for lithophane source images because it uses lossless compression. JPG compression artifacts translate to visible noise in the printed lithophane. If your source is HEIC or another format, convert to PNG at maximum quality.
What resolution do I need for a 3D printed lithophane?
Aim for 1000-2000 pixels on the longest side for a typical 100mm lithophane. Higher resolution provides no benefit since FDM printers cannot resolve details finer than their nozzle diameter. For resin printers, higher resolution (2000-4000 pixels) can capture finer detail.
Can I use a phone photo for a lithophane?
Yes. Modern phone cameras capture more than enough resolution for lithophanes. Convert HEIC photos to PNG first. Choose high-contrast subjects and good lighting for the best results.
Convert HEIC to PNG for 3D printing