Transparent projection drapes

vvvv beta question
9

with sharkstooth scrim you will get app.1/3 of your light power behind the screen.
e.g.: BGO - Gobelin - Scrim and bobbinet fabrics | PERONI
with Bobbinet = 1/2
e.g.: http://www.gerriets.com/en/products/collection/products.php?webcode=103107000&docID=3963&BZH=_2&BZU=_7&BZUU=1
so if you have front projection, you can place behind black backdrop,
cheapest is dekomolton
e.g.: http://www.gerriets.com/en/products/collection/products.php?webcode=104101000&docID=3964&BZH=_2&BZU=_1&BZUU=1
i think you have to go extreme sidewise with projector angle to avoid imaging behind, additionally you will lose power through unfavourable angle
there is way to set up rear projection if you can, but then you have troubles to hide projector’s glare behind the screen