LENScrop our image to the same aspect resolution as this,
then upload the image to a lithophane generator.
There are a few available online, but we used the
one at 3dp.rocks/lithophane. This provides some
options of different shapes that might be useful if
you’re trying to use your lithophane in different
ways, but we went with just a flat lithophane.
This generates an STL file that we can import into
our slicer as with any usual 3D print file. In the slicer
(we used Prusa Slicer, but any should work), you can
scale the object to exactly 82 × 45 mm. We had to
unlock the aspect ratio as it ended up being out by
about 1 mm without this, but it’s not noticeable in
the final print.
Common wisdom dictates that you should print
your lithophanes vertically, as this will give you
better resolution (a large brim will help it stay
attached to the print bed). We tried out a few ways
of printing and for this style of image (where most
parts are either very black or very white), we didn’t
notice much difference between them printing
vertically and horizontally (other than they printed
much faster when lying flat to the print bed).
A few dots of superglue attached the lithophane
to the back-light (we put them in areas that were
dark so they didn’t affect the image in any noticeable
way). That’s the image set up – we just need a way
of providing power.
The back-light is basically just a white LED, plus
appropriate diffusers and reflectors, so powering it is
just the same as powering an LED (even down to
the fact that they have a long leg and a short leg).
Like many people, we have stacks of USB chargers
lying around, so this was the obvious choice for
sending electrons in. All we needed was a micro
USB breakout board (these are available cheaply
from a wide variety of vendors online) and a single
220 ohm resistor to limit the current.
We soldered these up, but needed a way to
insulate the bare wires – after all, we didn’t want to
put it down on a metal surface and accidentally short
it out. We decided to use the hack-y option and
cover everything in hot glue. It’s not an ideal
solution, but it does work. Fortunately, we’ve been
able to hide all the glue on the back, and who looks
at the backs of pictures anyway?Above
The circuit on the
back is just the power
connected to the LED
with a resistor
Below
If your aspect ratio
isn’t quite right, you
can stretch it a little
when doing the
print scalingThe key part of
the aesthetic of
lithophanes is
how they’re lit