Not every room can be fully darkened for projector use, and this is exactly the problem ambient light rejecting (ALR) screens are designed to solve. Using specially engineered optical coatings, ALR screens are built to reflect light coming from the projector - typically positioned in front of or below the screen - while absorbing or redirecting ambient light arriving from other angles, such as windows or ceiling lights. The result is a picture that retains noticeably better contrast and colour saturation than a standard white screen in the same room.

This makes ALR screens particularly well suited to living rooms doing double duty as a home cinema space, where you want to enjoy a big-screen picture without needing to black out the room completely every time. They're also commonly paired with ultra-short throw projectors, since many ALR screens are specifically engineered for the steep projection angle these projectors use.

While ALR screens do involve a higher cost than standard projection material, the improvement in usable picture quality in a partially lit room is significant, often making the difference between a washed-out image and a genuinely punchy, cinema-like result.