Gain is in simple terms, the measurement of the reflective power of the projection screen. For example, light directed at a screen with gain 1.0 would be reflected back at the same brightness. A gain greater than 1.0 would mean that projection screen fabric increases the brightness of the projected image.
For places where ambient light cannot be adequately dimmed, for example outdoors, convention centres, office buildings, auditoriums etc. a high gain screen fabric is used to make up the difference by increasing the brightness and clarity of the projected image.
However, higher gain not always means good quality image. Unnecessarily high gain can result in an effect called “hot-spotting”. This occurs when a fabric has such a high gain that it begins to exhibit mirror-like properties. This would result in a bright “hotspot” in the screen, which is essentially an enlarged and blurred reflection of the
Viewing angle is a measurement of the maximum angle from the centre of the screen at which you can still see a quality image. Some projection screens reflect most of the light perpendicular to the screen, sending much less to the sides. This makes the screen appear much darker and more distorted, if the viewers are not in the optimum viewing angle. High-gain fabrics tend to have a lower viewing angle.
Another very popular feature of the projection screen fabrics is the acoustic transparency. It is the ability of the screen to allow sound to pass through with little/no interference. This is especially important in setups where speakers are places behind the screen, such as cinemas, auditoriums and home theatres.
Ambient Light Rejecting (ALR)
ALR screens, as the name suggest, reduce the impact of ambient light on the resulting image on the screen. For environments with uncontrolled ambient light, there is no better solution than an ALR screen. These surfaces are designed to achieve optimal ambient light rejection. This results in a bright, crisp image without glare – no matter how much light is in the room