I have enjoyed printing lithophanes in the past and there is a great online software that generates the STL files based on a picture you upload. Standard lithophanes are awesome and I'm always impressed by how much detail can be captured by different thicknesses in a piece of plastic. The only problem is that they're monochromatic. The goal of this project aims to change that by adding some color.

A newer online software ITSLITHO does all of the heavy lifting. This software works as described above where you simply upload an image, change a few settings and download an STL file. Additionally, it generates a tailored JPEG to be printed along with the lithophane. This image when placed behind the lithophane is what creates the color. The ITSLITHO website has a complete tutorial on how to use their software.

Toby, a good boy, is an excellent model and a perfect subject for this project.

Supplies

3D printer
White and Black 1.75mm PLA
LED strip lights (white/warm or RGB)
Wire
Tools
- Hot glue gun
- Soldering iron
- Wire strippers/cutters

Step 1: Generating the Files

The first step is to use ITSLITHO to generate the STL and tailored JPEG files.

Upload your image using the upload tab in the program.
Adjust the settings. I changed a few of the settings to generate the STL for my printer.
1. I wanted as close to a standard 4'' x 6'' sized picture so I adjusted the height and width of the shape. (I accounted for the width of the frame as well.)
2. I increased the minimum and maximum thickness to 1.2 and 3.6 respectively. The minimum thickness is used for the "lightest" part of the image and the maximum thickness is used for the "darkest" part of the image. My 3D printer does not handle thin prints very well so I adjusted the default values accordingly. You may have to make similar adjustments specific for your printer.
3. The next important setting, which is on by default so I didn't have to change it, is to turn on Positive image. This will generate the STL such that the darkest areas of the image are printed as the thickest.
4. There are a multitude of additional settings that can be adjusted but I had great results with the defaults.
Download the files. After you hit the download button, the files are generated and you have a few options. I chose to download the lithophane and color lithophane which gives you the STL and the JPEG.

Step 2: Modeling and 3D Printing

Now that I have all of the files its time to CAD with Fusion360 and 3D print. All STLs are provided below

Design the frame. I used the dimension of the lithophane to start. I modeled a simple rectangle and extruded to a depth of 30mm and then shelled it to have a wall thickness of 2mm. I made a small cutout in the back for the LED power cord.

Model additional parts. I wanted to make the lithophane a push fit inside the frame in the event I ever needed to adjust the LEDs so I designed 4 small corners to serve as a depth stop. My LED strip came with a IR remote control so I designed a holder for the back for storage.

3D printing. I sent all of my STLs to Cura, my preferred slicer, to generate the gcode. My print settings are below and will vary based on your pinter. I have a Monoprice Maker Select 3D printer V2.

Lithophane print settings
- Quality
  - layer height: 0.2mm
  - skirt/brim line width: 0.4mm
- Infill
  - infill density: 100%
  - infill pattern: Lines
- Material - PLA
  - print temp: 218 C
  - build plate temp: 60 C
  - retraction distance: 5mm
  - retraction speed: 25mm/s
- Speed
  - print speed: 50mm/s
  - infill speed: 50mm/s
  - travel speed: 100mm/s
- Disable Support
- Build Plate Adhesion
  - brim
  - brim width: 4.0mm
Additional Parts
- Quality
  - layer height: 0.3mm
  - skirt/brim line width: 0.4mm
- Infill
  - infill density: 20%
  - infill pattern: Grid
- Material - PLA
  - print temp: 218 C
  - build plate temp: 60 C
  - retraction distance 5mm
  - retraction speed 25mm/s
- Speed
  - print speed: 60mm/s
  - infill speed: 60mm/s
  - travel speed: 120mm/s
- Enable support (for remote holder)
- Build Plate Adhesion
  - brim
  - brim width: 4.0mm

Step 3: Add Color to the Lithophane

Now with the standard lithophane printed, you can add the color. The accompanying JPEG provided by ITSLITHO has formatted the size and optimized the coloring of the original picture. I printed the image on standard printer paper and cut the image out. I used all purpose spray adhesive to bond the color image to the lithophane. For a permanent bond, I sprayed both the back of the lithophane and front of the image then pressed them together. I was very impressed with the result after holding it up to the light.

Now, on to adding a permanent light source in the frame!

Step 4: Wiring LEDs and Lining the Frame

I purchased some inexpensive remote controlled RGB LED light strips that operate on 5V USB. The next step is to roughly lay out the LEDs into the frame and cut the strip to length. I wanted to wrap the strip around the edge then line the back with a few strips. I cut the strip down to size and soldered jumper wires between.

I inserted the LEDs into the back of the frame and started hot gluing them in place. Pay careful attention to the IR receiver on the strip to make sure that it is not obstructed. The strip has adhesive backing but does not stick well to the PLA so used additional hot glue to keep the strips in place.

The last thing to do is plug them in and test the LEDs in place. If they work, you're almost done!

Step 5: Assembly

After the LED's are glued in, the last step is to add the depth stop corners. Be sure to measure the thickness of the lithophane and use that measurement for placement of each corner. I used hot glue to secure the 4 pieces into place as shown in the images above.

Now press fit the lithophane into the frame. It should sit flush with the outside if you glued in the corners at the appropriate depth.

The last (optional) step is to glue the remote control holder onto the back of the frame. You're done!

Plug in your finished color lithophane and turn it on with the remote to enjoy! The white LED setting gives the best result but the other colors are fun to cycle through and can be enjoyed like a standard lithophane.

I'd love to see others' implementations and color lithophane projects. Happy Making!

Introduction: Lithophane in Color