I am a studio photographer by hobby... and I just happened to have White, Black, and Studio Gray backdrop paper in my garage I use for product photography...
After I got an AE700 projector I used a bed sheet and after getting irritated with it (lol i know) I actually made two different test screen using the backdrop paper; while it’s cheap and easy to do... not an ideal material and there was something lacking from the picture quality when you compare to a real screen.
I did learn one thing from my backdrop paper and that was to investigate more into the Gray color. I can tell you from my own experience the Studio Gray color was way too dark in color, a lighter gray would have worked much better. But I did see an advantage of using the gray since the contract was must better over the white paper (my room is very “bright”)
After all this fuss, I ended up buying a manual pull down screen from EliteScreens. For about $110 bucks, I got a nice 92” 16:9 with a matt gray finish and it’s just fantastic.
For the price, and convenience, I was thrilled... not to mention it looked much better than the backdrop paper.