Gain factor: luminance factor. In the context of home cinema, gain refers to a screen's ability to reflect light through its coating. This makes the picture brighter.
A gain factor of 1,0 means a matt white screen without any reflection. A screen with z. B. 1,5 Gain reflects the light 1,5 times. A gain factor that is too high, ie if it is above 1,8 to 2,0, can lead to a disturbing hot spot (see hot spot). Also he will Viewing angle smaller with increasing gain factor.