magkaiba ALR screen sa blackout cloth.. Blackout cloth is used to cover the windows to block ambient light from entering through the windows. The other side (white side) could also be used as a screen, but this isn't ALR screen
ALR screen normally is gray in color, contained more "reflective" elements on the screen to reflect as much light that is projected directly on it. While indirect light (ambient) is being "rejected". Adding more "reflective elements" has its negative effect, it will make the viewing cone a lot narrower or worse hotspoting...