Update: Projection Screens
We briefly mentioned that many screens available today have a blue or blue green tint to them, reflecting those particular colors more than the red end of the visible spectrum. The original thinking was to compensate for the yellowing of screens with age, and exposure to smoke. There is also the belief that a blue white is 'better' than a neutral white. The green side of tinting came from the idea of human beings seeing green better, therefore the reflectivity of green should be higher. Of course this reasoning is as ill advised as saying we should pre-emphasize the mid portion of the audio spectrum because we hear that frequency range better.
Many of the compromises made in screens, as in spectral response and light fall-off toward the edges of the screen, have been made in the name of improving the capability of the projector and or providing some immunity in less-than-good viewing environments. What is missing in that logic is the characteristic of the screen is a fixed solution to a variable problem.
While on the topic of asking the screen to 'fix' something wrong in the source, we'd like to briefly mention curved screens. While this has little to do with the screens we've developed with Da-Lite, it is part of the larger story of mis-using screen technology to compensate for errors elsewhere in the system.
The original idea behind curved screens for video projection, back in the days of the Kloss Nova-beam projector, was the screen had to be curved to get a high-enough gain to provide a useable amount of light for the viewer. I was even part of looking at curved screens for light output from video projectors from the early 1970s to the late 1980s. At the time it seemed to be the only way to get a useable amount of light from a video projector. The screen gain was often in the order of 15.0. You couldn't move your head without seeing a significant change in light output or color. The surface of these screens was often silver-coated to increase reflectivity. Just touching the screen left a permanent reminder of having done so.