Reflectance

How much light is reflected from an object’s surface. It is a function of Wavelength, so it is what defines an object’s inherent color.

The perceived color of an object is the product of its Reflectance and the Illuminant Spectrum. When the illuminant is approximately white (e.g. D65 white), the perceived color and Reflectance are very similar.

This is different from Reflectivity, which is a function of a material, not a given surface.

See also Transmissibility.