Best Lithophane Settings: Thickness, Layer Height and Print Speed

Most lithophane guides give you a list of numbers with no reasoning attached, which is why people follow them exactly and still get a muddy print. This page gives you the numbers first, then explains what each one is actually controlling — because two of them interact in a way that decides the whole result.

The settings

Setting	Value	Why
Minimum thickness	0.8 mm	Thinner is fragile and loses contrast
Maximum thickness	3.0 mm	Thicker blocks nearly all light and adds hours
Layer height	0.10–0.12 mm	Sets how many distinct greys you get
Orientation	Vertical, on its edge	The single biggest quality factor
Infill	100%	Any gap shows as a bright patch
Top / bottom layers	0	With 100% infill they add nothing
Perimeters / walls	2–3	More and the walls dominate the image
Print speed	30–40 mm/s	Fast printing smears the fine surface detail
Nozzle	0.4 mm or smaller	0.6 mm cannot resolve the detail
Filament	White PLA	Diffuses evenly, well-understood absorption
Cooling	100%	Thin walls need it
Size	100–150 mm wide	Below 80 mm the detail has nowhere to go

That table will get you a good print. The rest of this page is about the three decisions inside it that people get wrong.

What your layer height controls depends on orientation

Almost every lithophane guide says layer height sets how many shades of grey you get. That is true — but only if you print the panel flat, which is the one orientation everybody, including this guide, tells you not to use. It is worth untangling, because the two cases behave completely differently.

Printed flat, the thickness runs along Z. It can only change one whole layer at a time, so the number of greys is simply the thickness range divided by the layer height:

Layer height	Greys available flat (0.8–3.0 mm)
0.08 mm	28
0.10 mm	23
0.12 mm	19
0.16 mm	14
0.20 mm	12
0.28 mm	8

Twelve shades is roughly what a 1980s computer display had — fine for a high-contrast graphic, hopeless for a face or a sky, where it shows as banding.

Printed upright, none of that applies. The thickness now runs across X and Y, where a modern variable-width slicer resolves wall thickness to a few hundredths of a millimetre rather than a whole layer. You get hundreds of tonal steps instead of a dozen. Layer height still matters, but it is now setting how many horizontal lines the picture is drawn with — a 75 mm tall panel at 0.12 mm is 625 lines; at 0.28 mm it is 268.

So “use 0.10–0.12 mm” is the right answer either way. The reason is just different, and if you have been told layer height caps your greys while also being told to print upright, both things cannot be the headline.

The thickness range is the other lever, and it works in both orientations. Going from 0.8–3.0 mm to 0.8–3.6 mm at 0.12 mm layers takes a flat print from 19 greys to 24.

Our lithophane maker has an orientation control and applies the correct quantiser for each, so the preview shows flat-print banding only when you are actually printing flat.

Print it standing up, not flat

If you change one thing on this page, change this — and unlike most printing advice, it has been measured.

A 2024 study in Polymers tested six FFF parameters against how much light actually passes through printed PLA. Orientation was the largest single factor of the six:

Orientation	Light transmitted
Portrait (upright)	246.0 lx
Landscape	240.8 lx
Flat	194.2 lx

That is a 27% swing, larger than the effect of nozzle temperature, print speed or extrusion multiplier. On top of that, upright printing is what moves thickness out of the layer-quantised Z axis and into the finely-resolved XY plane, as described above.

The same study found layer height was one of the weaker factors for raw transmission, and non-monotonic at that — 0.05 mm and 0.30 mm both transmitted more light than 0.10 mm. That is about porosity, not image quality, so it is not a reason to print coarse. It is a reason not to believe layer height is the master control.

Vertical printing needs a brim, because the footprint is small and tall thin objects tip. It also needs a slower first layer. Both are worth it.

Thickness sets your contrast, and it is not linear

The range between your thinnest and thickest point decides how much contrast the finished piece has. What surprises people is how quickly it changes, because light transmission through plastic is exponential, not linear.

Light passing through a material follows the Beer-Lambert law:

I = I₀ · e^(−μt)

where t is thickness and μ is how strongly the material absorbs. Doubling the thickness does not halve the light — it squares the attenuation. In practice, for white PLA:

Thickness range	Approximate contrast ratio
0.8–2.0 mm	5:1
0.8–2.5 mm	9:1
0.8–3.0 mm	17:1
0.8–4.0 mm	64:1

Below about 8:1 the print looks washed out no matter how good the source photo was. Above about 64:1 the dark areas stop being dark and start being black holes with no detail in them, and your print time has roughly doubled.

0.8–3.0 mm sits in the useful middle. That is the only reason it is the standard recommendation.

This same exponential is also why most free lithophane generators produce flatter results than they should — they map brightness onto thickness in a straight line, as though transmission were linear. Why lithophanes come out washed out covers what that does to the midtones, with a side-by-side.

Curved and cylinder lithophanes

A flat panel needs a stand and a lamp behind it. A curved one stands up on its own, and a full cylinder becomes the lampshade — drop an LED tealight inside and it is finished.

The geometry is one number: how far the panel wraps.

Wrap	Result	Inner diameter for a 100 mm wide image
0°	Flat panel	—
60°	Gentle arc, still needs a stand	191 mm
120°	Stands on its own	95 mm
200°	Deep curve, wraps a candle	57 mm
360°	Closed cylinder lamp	32 mm

The relationship is just arc length over angle: a 100 mm wide image wrapped through 120° sits on a radius of 100 / (120 × π / 180) ≈ 47.7 mm, so a 95 mm inner diameter.

Two things to watch. A tight curve relative to the material thickness distorts the picture around the bend, so keep the diameter to at least six times your maximum thickness. And if you are making a cylinder for a tealight, work backwards from the light: a 60–90 mm diameter is the usual range, which means an image 190–280 mm wide. Our lithophane maker shows the derived diameter live and warns you when the cylinder is too narrow for a standard base.

Curved pieces print upright by their nature, which is the orientation you want anyway.

Filament choice changes the maths

Different plastics absorb light at different rates, so filament is not a cosmetic choice — it changes what thickness you should be printing at.

Filament	Behaviour	Verdict
White PLA	Even diffusion, moderate absorption	The default. Start here.
Natural / clear PLA	Passes more light	Brighter but flatter. Needs a wider thickness range.
Ivory / warm white	Higher absorption	More contrast, warmer tone. Good for portraits.
White PETG	Similar to PLA, glossier	Works. Slightly more stringing risk on thin walls.
Grey or coloured	Absorbs heavily	Needs a genuinely bright backlight.
Silk or sparkle	Additives scatter light unpredictably	Avoid.

Avoid anything with glitter, marble effect or colour transitions. Those additives scatter light in ways that have nothing to do with your photo.

Choosing and preparing the photo

The settings can only do so much with a bad source. What works:

• High contrast, single clear subject. Faces, pets, silhouettes, buildings against sky.
• A simple background. Every millimetre of thickness range spent on background clutter is range not spent on the face.
• Crop tight, before you upload. This matters more than any slider.
• Slightly overexposed beats underexposed. Dark photos map into the thick end where you have the least tonal resolution.

What does not work: busy group photos, fine text, anything relying on colour to separate two objects — colour is discarded, so a red shirt and a green wall of the same brightness become the same thickness.

Print time and material

A 100 × 75 mm lithophane at 0.12 mm layers, 100% infill, printed vertically, is roughly:

• 13–18 g of filament
• 4.5–6 hours at 35 mm/s
• 11–15 cm³ of material

The spread is the photo itself: a dark image sits in the thick end of the range and uses meaningfully more plastic than a bright one at identical settings.

Dropping to 0.10 mm layers adds around 20% to the time. Going to 150 mm wide roughly doubles both figures. You can check yours exactly with the print time estimator and the cost calculator.

Common problems

Banding across smooth areas. If you printed flat, that is layer quantisation — reprint upright, which mostly removes it. If you printed upright, it is more likely flow inconsistency or a source image that was already posterised.

Washed out, low contrast. Thickness range too narrow, or the generator used a linear brightness map. Increase maximum thickness first.

Dark areas are pure black with no detail. Maximum thickness too high. Come back to 3 mm.

Visible gaps or bright speckles. Infill is not at 100%, or the flow rate is under. Both show instantly on a backlit part.

Detail smeared and soft. Printing too fast. 30–40 mm/s.

It looks fine flat but bad on the wall. It is being lit from the front. A lithophane needs the light behind it — a window, an LED panel, a phone torch.

Getting the file

You need a generator that turns your photo into an STL heightmap. Ours is the lithophane maker — it runs in your browser, nothing is uploaded, and it shows a simulated preview of what the print will look like backlit, computed after quantising to your chosen layer height. That last part matters: you can see your banding before you print rather than after.

If you want a raised plaque rather than a backlit panel, the image to STL converter does relief mode off the same engine.

Then check the mesh in the STL viewer before slicing, and print it standing up.