If you want a very simple to do screen, go buy a 4 x 8 piece of masonite. One side is perforated, one side is smooth, your choice.
Attach to your wall using mirror supports, available at hardware stores. Buy a gallon of pastel base white and an oz or two of lamp black colorant, then mix to a very light shade of grey. Be careful, a little black goes a long way. I suggest using a quart jar rather than mixing in the whole gallon.
Using the paint method gives you GREAT flexibility for trying different shades of grey to best suit your needs.
E-mail me if you want more info.