celexon electric Professional-Series

Gain factor:
The gain factor (or also called gain) is used to assess the reflection behaviour of screens and describes the light gain achieved in contrast to the brightness of the projector. A gain factor of 1.2 indicates that a screen reflects 1.2 times more in a given direction than a defined white standard surface. The gain factor is always given for the straight viewing angle of 0 degrees.

Hot spot:
A hot spot is a brightening in the centre of the image on a screen. These disturbing artefacts are created by the direct visibility of the projector lamp and only occur on screens with a very high gain factor (1.8 to 2.0).