The term luminance is used when talking about how illuminated objects appear to an observer.
- Luminance is a measure of the intensity of light that reaches the eye.
- So we can talk about:
- The luminance desert sand under moonlight.
- The luminance of a road surface under street lights.
- The luminance of a book cover in sunshine.
- Luminance can be measured and so is an objective term rather than a subjective experience.
- The light produced by a table lamp can be described in terms of luminosity, the amount of light that is then reflected from a surface towards an observer can then be measured in terms of luminance.
https://en.wikipedia.org/wiki/Luminance