What does a screen gain of 1.0 represent?

A screen gain of 1.0 indicates that the screen reflects light equally in every direction as it receives it, meaning it has a neutral reflectance. This gain value serves as a reference point -- a gain of 1.0 does not amplify or diminish the brightness of the projected image in comparison to a matte white surface under similar lighting conditions. The screen reflects the light from a projector uniformly, providing consistent brightness across the viewing area.

In contrast, variations in gain above or below 1.0 would mean the screen either amplifies (gain greater than 1.0) or diminishes (gain less than 1.0) the brightness of the image. A higher gain could be due to a reflective surface, while lower gain suggests a diffusion of light, resulting in less brightness. Therefore, the concept of gain is essential for understanding the screen's interaction with ambient light and how it impacts the viewer's perception of brightness and image quality.