If you want to make it look slick, add 1% per weight UV glow powder to UV cured resin. That’s my recipe for a resin-based diffuser for LEDs. You have to be careful with the application though because resin is kind of heavy.
If you’ve been following my posts on the discord the ws2812 test rig I showed yesterday has its entire faceplate covered in an early version of my diffuser resin.
It’s also fun because you can draw patterns on the surface that will remain after the LEDs are turned off because the diffuser holds a bit of the light and then re-emits it later.
I made a few sheets of it, if you shoot it with a laser pointer you could draw lines and patterns on it. It would make for a really fun slow scan CRT emulation art piece