I found that my eye line was precisely at the point where the gain drops off dramatically.
At this position the sparkles dominate the picture, yet move slightly into or out of the viewing cone and they are less distracting.
I would say the best picture is within a 20 deg cone - so only 10 deg either side of the centre of the lens and 10 deg above or below the centre of the lens.
Easier to achieve in a longer room than mine, unfortunately I can only project across the width of the room and the screen sits in front of a chimney breast in front of a plasma.
I have raised the sofa 2 inches which has helped the problem a little.
I am going to find a way of lowering my projector a little further.
When I view the adjacent wall to the screen, I can clearly see a bright halo of light on the wall, which demonstrates the viewing cone. It is fairly small, but then the wall is only 3m away from the screen.
My advice if buying this screen is to do some basic trigonometry to see if your head ends up within a 20 deg cone. You only need to know the position of the lens (light source) and the distance between the lens and the screen. (I very much doubt the lens shift can have any significant bearing on a retro reflective screen - can anyone confirm that?)
For someone in a dark room but with reflected light washing out your picture (anyone who has not painted their room and ceiling black or grey or used roller blinds around the room) and if your head would fit into the cone then it is a very good solution to a punchier picture, better blacks AND brighter images (=more contrast
) - although you may find the texture a little distracting but I think most people would accept this trade off..
Update 12/11/09: Actually the texture is more than distracting it seems to effect resolution (or perceived resolution), the texture interferes with the pixel pattern on the screen. Mine is the pull up version, I assume the material must be identical to the fixed and pull down versions.
MY PJ is only a 720p projector, I imagine a 1080p would be even more affected. My white DIY white screen & UK black widow screen look better with a creamy smooth, in comparison, image. However the ambient light rejection and increase in contrast of the graywolf counterbalances the loss of detail, for me, at the moment. It's a real dilemma . The only screen I know that does what the graywold can do but has a fine enough coating not to interfer with resolution is the stewart grayhawk G3, which costs
, so I can't complain for £120.
As has been said before room redecoration and a white screen is the best but I cannot paint the living room grey/black