I designed this retro TV Box for displaying classic movie frames in lithopane form. It works with a 30mm LED light that screws in at the rear:
https://www.amazon.co.uk/Submersible-Waterproof-Underwater-Colorful-Aquarium/dp/B07B8MX591/ref=sr_1_8?crid=1FW7AAUC2X97M&keywords=pool+led+lights&qid=1702838689&sprefix=pool+led+light%2Caps%2C90&sr=8-8