Color - Brightness (Light Perception)

About

Brightness is:

• a subjective attribute of light
• a perception

It cannot be measured objectively (but can be scaled, e.g. in %).

The perception:

• is not linear to luminance,
• relies on the context of the viewing environment.

For instance, a monitor can be adjusted to a level of light between very dim and very bright.

The inverse of brightness is dullness.

Formal definition

The brightness is:

• the value of an area judged
• relative to the brightness of a similarly illuminated area that appears to be white (ie highly transmitting).

It is then the representation of variation (relative) in the perception of a color or color space's brightness.