Measures the light-reflecting ability of a projection screen. The higher the number, the greater the amount of light reflected back to the viewer(s).

A measurement of the reflectivity of the screen. High gain screens were necessary for old projectors with low light output. However, teaming a high gain fabric with a contemporary projector will result in two major negatives - a narrow viewing angle and colour shift. Matte white (gain = 1.1) is best for contemporary projectors. See Screen Materials.

The amount by which a reflective screen (or surface of some sort) reflects light hitting it.

A measurement usually made perpendicular to screen center of the luminance transmitted by the screen, divided by the luminance radiating from the projector.

A measurement made to determined the screen reflectance. The higher the number, the greater light transmitted to the audience.

Gain is a property of a projection screen, defined by how much brightness is visible from the screen's centre when the viewer is looking at that point on-axis to the centre. Gain is controlled by diffusion of the screen, and governs the degree which light from the projector is scattered.