Step 1: The Pictures

I found several pictures of optical illusions on the internet and chose four.

Step 2: The Transforming Into a Lithophane

I used 3dp.rocks to transform the pictures into a lithophane.

Model settings: 3 mm thickness

Image settings: postive image

Step 3: The 3D Printing

I used ideaMaker to repair and slice the lithophane. I've printed all my lithophanes that way so far: no infill, 10 shells and it works well for me.

(Tip: 10 shells are more of what actually would be needed but with 10 shells you are on the save side.)

My gorgeous little Ender 2 3D printed the lithophanes in white PLA filament.

"Baingio Pinna & Gavin J. Brelstaff" illusion

- Printing time: 2 hours and 33 minutes / Size: 100 mm x 100 mm x 3 mm

"Dancing Dots" illusion

- Printing time: 2 hours and 33 minutes / Size: 80 mm x 80 mm x 3 mm

"Akiyoshi Kitaoka rotating snakes" illusion

Based on a black and white picture:

- Printing time : 3 hours and 2 minutes / Size: 90 mm x 67,5 mm x 3 mm

Based on a colored picture:

- Printing time : 2 hours and 24 minutes / Size: 79 mm x 71 x mm x 3 mm

Step 4: The Optical Illusion

The "Baingio Pinna & Gavin J. Brelstaff":

Move your head: go forth and back. The inner circle should roatate.

The "Dancing Dots":

Try to focus on one of the white dots and black dots beginn to "dance".

The "Akiyoshi Kitaoka rotating snakes"

I can't see any rotating snakes in the lithophanes.

Step 5: The Conclusion

I figured out: Black and white photos will work better (at least on my 3D printer with a single extruder), which is logical due to the shades of grey character of a lithophane printed in only white filament.

When I turned a color photo of an optical illusion into a black and white photo, immediatly the illusion either was completly gone or hardly to see.

So I proceed to just use "original" black and white photos of an optical illusion.

In case of the "Akiyoshi Kitaoka rotating snakes" the lithophane I wasn't successful - no matter which color the picture originally based on.

This is the end of my little experiment with mixed results. I'm sure there are more options to 3D print the models (negative image for example) to get it work. But before I run out of filament I'd rather stop at this point.

Have you tried this yourself? Please let me know your experience with this topic.