HOME > Ambient Light Rejection screens from Elite, Screen Innovations, and Microlite
Ambient Light Rejection Screens
August 5, 2015,
EDITOR'S NOTE: This article has been expanded and updated to include eleven current models of ALR screens. Please click here for the new review.) 3/03/16
In recent years, projectors have made their way out of the darkened home theater environment and into the living room and family room. But one of the downsides of this move is that, in living rooms and dens across the world, it is often difficult to control ambient light. Errant light, whether from windows, lightbulbs, or white walls, can be the death knell for contrast and an engaging, three-dimensional image.
As such, all players in the projector game have been busy working on ways to combat ambient light. Projector manufacturers have made brighter projectors, while screen manufacturers have been busy creating screens that enhance contrast and reject ambient light. This shootout features three such products from Elite Screens, Screen Innovations, and newcomer Microlite. Through different applications of ambient light rejection (ALR) technology, each manufacturer has created a compelling product that can give you a sparkling, high contrast picture in any room of your home.
To understand how an ALR screen is different from a regular screen, we need a quick physics lesson. Most surfaces reflect incoming light in all directions more or less equally. That's why you can look at a painting, for example, then take three steps to one side and see the same painting. These surfaces are called diffuse reflectors. The surfaces that we typically think of as "reflective," like mirrors, are called specular reflectors - they reflect light at an angle precisely opposite the one at which that light arrived.
All projector screens are diffuse reflectors to some degree. Some, like the Stewart Studiotek 100, are nearly perfect diffuse reflectors. Other screens are partially diffuse and partially specular - they reflect light more in one direction than in others, usually to make the image brighter for people sitting in a certain area. These screens include most high-gain models as well as the silver screens used for passive polarized 3D systems. Many ALR screens also operate in this way. For a quick refresher course, our 2004 article on screen gain is still valid today.
By selectively reflecting light, you can position the projector and screen in such a way that the projector's light is bounced towards the audience's eyes, while the other light in the room is bounced in some other direction. This means that modern ALR screens have a "sweet spot" angle where the image will be at its brightest and a corresponding ideal seating area for the audience. Light coming from other angles is partially bounced away, reducing its deleterious effects on the projected image.
This isn't magic - just physics. ALR screens only work if the ambient light and the projector's light are coming from different directions. If you have your projector in the back of a room with a bright lamp sitting right beside the lens, an ALR screen won't do much for you. But if you're fighting against the reflections from white walls, the incoming light from overhead lamps, or the sun coming through a window off to one side, you're in luck.
Some ALR screens are also optical, meaning they have a lens-like element in the screen itself to help direct light back where it is needed. Optical screens tend to be semi- or completely rigid, making them less flexible than traditional screens. However, some newer optical screens can still be rolled up (albeit in larger rolls than their non-optical cousins), allowing them to be shipped in standard screen packaging.
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