I recently wanted to setup a rear projection screen for a family event and almost fell off my chair when I priced out what it would cost to purchase one. After some googling I saw some posting where people had used sheets or something else that is semi-transparent, so I thought I would give that a try. I hung a variety of different things up in a doorway to test their rear projection capabilities and ended up using a $5 frosted shower curtain that seemed to work the best. Ironically a more expensive shower curtain ($15) did not work as well since it was too thick and didn’t provide enough light pass-through.
The light shower curtain needed something to force it to hang straight, so I used 2 thin pieces of wood I had kicking around (a long dowel would also work good) and simply wrapped the shower curtain around the wood once and then stapled it for strength. A couple pieces of wire attached to the wood provided a quick way to hang it. Some pictures are below of how it worked and is put together.
This is the screen in action. Was very crisp and bright:
Top wood support with wire:
Bottom support to stretch the screen with the projector in the back. The wrinkles are not visible at all from the front when you are using it. If you wanted to eliminate the wrinkles hanging it up in a moist bathroom or shower would allow it to stretch out more.
Here is the bag from the shower curtain I used (cheapest one they sell at SuperStore):