TL;DR Why not create a full color edge-lit display, so that you can convert any image into an awesome full color edge-lit lithopane. Also, I made a lot of mistakes, and learned some things. No easy access to laser cutter so bothered friend to cut them. Skip to the next step for the instructions.
I always thought Edge-lit signs were really cool. Just etch a piece of glass or plastic and light it from the edge using some leds. You could make the sign as intricate and detailed as you want, as you don't have to rely on other limiting factors of led signs, like the diameter of the leds. You also don't need to worry about the power consumption like you would for a large led display or sign. They also just look really awesome!
One thing about edge lit signs however is that you can usually only use one color (based on the color of leds around the edge). Doing some research I have found some versions with multiple colors, but they usually print logo's on the plastic and light them up with white led's or use 2 pieces of plastic for 2 specific colors in a logo. I wanted to go further!
Why not separate a photo into it's Red, Green and Blue colors. Then combine them inline to create a full color light up photo. Since White light can be created with only Red, Green, and Blue colors, we should only need those 3 colors, plus Black. For the Black layer, we will use some black paper or maybe some plasti-dip on the very back.
So how to go about this. Red, Green, and Blue will be easy to create, but what about all the other colors? Well if you have ever played with some RGB Leds or Neopixels, you know that by adjusting the level of each channel, you can create many different colors. I wasn't sure how it would actually turn out though, so I had to just give it a try.
I had alot of trial and error, but I will show you my mistakes and assumptions, so you don't make them. This is very much an experiment, so if you think you can make it better, then please do! I would love to know if anyone else has success with this! Share your results!
Since this is a bit of trial and error, I was bound to have some problems with my theory, but here are some questions and problems that I faced from the start.
How do I manipulate the photos? (I found alot of useful information and tutorials on GIMP)
How well will the other colors turn out? (I decided that even with my limited access to a laser cutter, I should probably start with a test image to see what colors show up more than others)
Will the colors from the back pane still be visible from the front? (I wasn't sure, but eventually found a method that seemed to work, and some that didn't)
Will the Red, Green, and Blue colors blend together? (Sorta, but we have to use some special filters. White was a little tricky however)
Parallax......How will the image and colors look with gaps between each pane of acrylic? (This method is very sensitive to the viewing angle, but it looks awesome from all angles!
No Laser Cutter! (This is a big one!!! I don't own a laser cutter, and my Makerspace doesn't currently have one either. Luckily I have a friend who built his own, but it is fairly hard to get access to, especially when you are doing many iterations and making many mistakes. Overall, it took 3 months from idea to this being posted)