One of the most universal and important measurements to illustrate a projection-screens capability.

Peakgain tells you how much light you will see on axis. To look at a screen on axis is to look at the centre in both horizontal and vertical direktion.

Peakgain is a concept from the photographic industry to describe the quantity of light reflected from a surface.

Peakgain 1 is defined to be the amount of light reflected from Calsiumcarbonate, when light is PROJECTED on the surface. This means a bloc of magnesium sulfat has a reflection-ratio of 1:1 (or GAIN 1).

 

Screens with a higher peakgain concentrate the reflection from the screen toward a minor area, which implement a more narrow viewing-area and possibility of hot-spot. Hot-spot is when you can se or sense the light-source palcement on the screen.

It is not possible to get more light from any projection-screen than the amount of light projected to the screen.

A white screen has brighter image (higher gain) than a grey screen, but the grey surface creates an image with more contrast (colour-saturation).

Basically a requirement of brighter image require a more powerful projector, but the correct choise of screen can help you directing the amount of light from a projector to the spectator.