Specifically Terrestrial Albedo Factor
When walls or exposed roofs (either flat or pitched) are selected then the colour (and hence reflectance values) may also be defined by clicking on the Define Colour buttons in both the Wall Details and the Ceiling Details forms. Scientifically, varying reflectance as a function of surface colour is described under the phenomenon known as albedo factor.
Typical terrestrial albedo factors.
|0.08 to 0.15
|0.15 to 0.18
|0.50 to 0.70
|Planet Earth average
As can be seen, the higher the value the more reflective the surface. Then conversely of course lower values correspond to darker surfaces.