Ambient light rejection or ALR is, arguably, necessary in the majority of installations. We’re not just talking about light from windows, where you can draw a blind, but reflected light from pale walls, floors, flipcharts, whiteboards etc. These sources of light are very hard to control.
ALR doesn’t literally reject light, but rather diverts ambient light away from the viewer’s field of vision. There are two types – lenticular and specular. Lenticular has tiny lenses in the screen fabric. It can be highly effective but has a couple of downsides. There is a restriction on how high screens can be made. The fabric can’t be rolled, so it’s only suitable for fixed frame screens. And frankly it can be temperamental in operation.
For example, our partner Draper focuses on specular ALR. Their screens are vinyl based, so flexible. They apply a light reflecting formula to a screen – this can be applied to any screen surface so they can give any of their products ALR properties. On a normal screen, ambient light is reflected back at 180 degrees, i.e. into the viewer’s eyes. The formula contains fibres that reflect back ambient light at a 45 degree angle up or down. Screens are often given an ALRV (ambient light rejection value) expressed as a percentage. This represents the amount of light rejected or rather, diverted.