The issue being how thick the paint is. It will be what blocks the light. What I have seen as the best solution is it is machine printed, which allows a thin and even coating.
I agree that your best results will come with experimentation.
Yeah, you REALLLY want to do each paint application "
in one", no going back over or touching up as that will make that area "thicker". The specific treatment we had used in the above mentioned application somewhat fades from my memory but I believe it was simply applied with a
hudson sprayer in a few different layers.
Experienced painters will know the deal from any back-lit drops.
There are a number of materials you can try of course ranging from
muslin to whatever. Everything will take the light from the front and from the back differently, and give you a different resulting look. I wouldn't use RP
screen material as that would be an expensive waste.
Do-Up a few different option samples and shine them from the back with a
projector and with whatever conditions you expect from the front, be that direct or ambient lighting. Use whichever performs best, and the paint/dye treatment you give it will have a different kind of
effect depending on the material itself.