I have a thin sheet I am using for an outdoor screen, I can see the PCV through the sheet.

A lot of light is wasted because it is so thin, any ideas to make this fabric any better?

I want to keep it collapsible so i dont want to worry about any perminant wrinkles

How about paint the backside with silver metalic ...

Have you thought of trying some aluminized mylar? It is super thin and flexible, but strong. Put it behind your sheet and it will reflect back the light you are losing through it.

If you haven't heard of aluminized mylar before, you'll probably know it as a "emergency blanket" or "survival blanket", the kind that is sold at outdoor supply stores, it looks like this
Emergency blanket
If the fold lines take too long to flatten out, stretch it out and go over it with a hair dryer.

Tgrenwood

This is exactly what i'd like to try. If you do try the mylar, please let us know what you thought. What is the thin sheet by the way? Are you satisfied with the whites and colours? Any hot spots?

i was not satified with the sheet because the image was a bit Dim and you can see the PVC behind it. i ended up buying some BO cloth for around $30, WOW, works really really well, and it is really bright too!