Lithophanes: prepare an image you may use, set the relief and test backlighting

Start with an image you are allowed to use

Before conversion, choose an image you are allowed to print and, depending on your project, share as a model or lithophane. Finding an image online does not by itself specify the permitted uses; the guide to licenses and rights helps you check the applicable listing or permission.

The Prusa post treats a graphic drawing conversion and a photo lithophane as separate workflows. Its advice about simple images with sharply separated colors belongs to the first workflow; do not treat it as a condition excluding photographs from lithophanes. To prepare your image, you could crop the subject and inspect a grayscale preview, then compare the relief and backlit plate.

For a lithophane, Prusa’s 2018 article gives 500 × 500 pixels as an example of a reduced image: it says that was enough for its model and shortened processing. That value belongs to this workflow; it does not set an input resolution for every generator or model size.

How the generator turns pixels into relief

In the tool Prusa described in 2018, the post says pixel height depends on the share of black (black = 0, white = 1) and that the Positive Image / Negative Image control inverts the image for that example. This is not a polarity rule for every generator; check the preview in the tool you use.

That inversion logic belongs to the generator described in the post. A different tool may apply the opposite polarity by default, so do not rely on a universal rule. Look at the 3D preview instead: the dark areas of your photo should become the thickest areas of the plate, because thickness blocks light.

In the generator settings cited in the 2018 post, Prusa recommends 0.4 mm for “THINNEST LAYER (MM)” and leaving the other settings unchanged. This is the example for that external tool, not a setting tested or recommended here for other generators. The post then says to download the model and open it in PrusaSlicer; the current availability of the tool is not established by this older article.

Thickness, scaling and orientation in the slicer

In its 2018 workflow, Prusa says not to resize the model on Z in PrusaSlicer because that changes relief height; it says X and Y may be adjusted. Treat this as the instruction for that example. Check the layer preview to confirm the relief and dimensions match the generated file, without assuming that scaling preserves the optical result.

The 2018 post favors flat printing to avoid wobble from a thin upright plate. This concerns its example and does not guarantee your plate’s finish or lighting result. In your trial, compare the surface produced on the chosen bed, adhesion, and relief detail before settling on an orientation.

For the PrusaSlicer reference described in Prusa’s knowledge base, the MK3S stock 0.4 mm nozzle is associated with a 0.45 mm extrusion width; the page says perimeter widths are approximate and depend on slicer settings. Use this reference to inspect your profile preview, not as a universal detail limit for lithophanes.

The slicing setup Prusa documented

Prusa’s 2018 post gives 0.10 mm as the layer height for its example and mentions 0.05 mm with a 0.25 mm nozzle as an option aimed at the best quality in that workflow. These values are not a universal recipe for another geometry, material, or profile; treat them as test parameters attributed to that post.

In the print settings, the post sets layers and perimeters as follows: one perimeter, one solid top layer and one solid bottom layer. For infill, it specifies a rectilinear pattern at 95 percent. These values describe Prusa's workflow with PrusaSlicer and an image processed through the generator it cites. They are not prescribed for every material, generator or curved geometry.

Prusa also reminds you, in its modeling guide, to make test prints before considering a design final. Apply that advice here: a small test plate with identical settings can help you check polarity, detail and bed adhesion before choosing the final size.

Which filament lets the light through

According to the Prusa blog, the best results come from a light material color, ideally white or cream, though the post also mentions silver and even purple. Above all, it states that quality always depends on the filament manufacturer, since not every filament transmits light and not every filament gives a perfect lithophane. The post encourages experimenting.

Filament color alone does not predict its light transmission. Prusa recommends light colors for its example and says transmission varies by filament. Compare a small plate using the spool and light you intend to use; that trial applies to your combination of material, thickness, and lighting.

Prusa’s Knowledge Base says filaments chosen for outdoor use or high mechanical resistance may reproduce small details less well than PLA. That guidance concerns FFF design and does not rank their light transmission. For a lithophane, check detail and light on a test plate with the selected grade.

Backlighting: testing without overheating the plate

The Prusa blog describes a lithophane as a work in thin, translucent material whose image only appears clearly in front of a light placed behind it, and whose look changes with the light source. Check the result with the intended light as well as the slicing settings. Stick to a lighting device sold for this kind of use, with low heat output, used within the conditions its manufacturer specifies. Do not modify its wiring and do not press a hot bulb against the plate.

To compare plates, you can record the spool, profile, lamp-to-plate distance, and light setting used. This record helps compare trial conditions; it does not by itself identify the cause of a difference in appearance.

Finally, the post mentions an upgrade for makers already comfortable with the process: adding colors to the back of the plate with ordinary markers. Try it on a test plate before touching the gift version, and judge the result in front of the same lamp you will use afterward.

Sources and limits

• Prusa — Von 2D zu 3D, October 5, 2018
• Prusa — Modeling with 3D printing in mind

We organize manufacturer and community documentation; we have not measured these products ourselves. The manual for your exact model takes precedence over general guidance.