# R—Reflectivity

> [!note] 此页面尚未翻译，以英文显示。


The Mean Reflectivity index R represents the average reflectivity value of the surface, or a value for how the surface interacts with light, contributing to its visual characteristics such as gloss and brightness. 

Reflectivity is an absolute measurement but uses a non-standard unit (arbitrary units [arb'U]) specific to the measurement system.