Originally Posted by Drexler
The gain of the screens are very sensitive to the angle you measure them from. In my experience especially the HD screens have a large drop off unless you're exactly in the sweetspot both vertically and horizontally. It might well be you can get opposite result depending on your measurement setup.
Yes, I'm aware of proper positioning of the meter, and I optimized my meter on each sample for the measurements. Also, these screens are not very directional with a half-angle of 75 degrees and 80 degrees for the HD Progressive 1.3 and the Stewart 130G3 respectively. I think you might be thinking of the Da-lite HP screens which are quite difficult to measure off the screen due to their very directional behaviour. I know, I had a HP2.8 screen. I'm also certain Craig and Jeff are quite knowledgeable, especially Jeff as he has measured the directional properties of many screens