I’m guessing that’s about how it’s done. Probably for commercial jobs they have some sort of disposable sheet for the final color & wear layer — I know photogs have this sort of thing in white for regular photo studios.
Though, Googling I see that many chroma key screens are simply cloth hung on a rod.
Here’s a good assortment of stuff: http://www.filmtools.com/chromkeyfab.html
So convenient a thing it is to be a reasonable Creature, since it enables one to find or make a Reason for everything one has a mind to do. –Benjamin Franklin
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Here's a link to PhotoStudio type prefab "Infinity Corners"
http://www.calumetphoto.com/Studio/Backgrounds,+Coving,+Cycloramas/Infinity+Walls/