Originally Posted by umr
The attached file contains results of screen material tests for some Carda, Da-Lite and Stewart screen materials.
The screen materials tested in this report in no way encompass all of the materials on the market, but does explore some of the products from Carada, Da-Lite and Steward. These include the Classic Cinema White and Brilliant White from Carada. Da-lite materials include Cinema Vision, Video Spectra 1.5, Da-Mat®, HD Progressive 0.6 and the HD Progressive 0.9. Stewart Filmscreen materials included StudioTek 130 G3, FireHawk G3, and SnoMatte 100. Data in this report includes results from previous tests to make it easier to compare results for various products.
Thanks for providing this excellent report!
I would like one clarification if you don't mind.
You define your 18-degree measurement as "Measurements at this angle were taken 18 degrees to the side and 6 degrees down, but are of the same location as the 0 degree point on the screen."
You also say that "the projector in this case was ceiling mounted in the center of the screen horizontally and vertically above the screen."
So, I am clear that 18 degrees to the side is with respect to the light path from the projector, because the projector is centered with respect to the screen.
Is the "6 degrees down" with respect to a line perpendicular to the screen surface, or with respect to the light path from the projector to the screen?
I would guess that it is with respect to a line perpendicular to the screen surface because with a ceiling mounted projector and measuring a spot 32.5" below the center of projection, it would be hard to get just 6 degrees between the light path and the viewer.
If the "6 degrees down" is with respect to a line perpendicular to the screen surface, what is the angle between the light path from the projector to the screen and the screen to the viewer (the total angle of reflection)?