Albedo is defined as the ratio of reflected to incident radiant flux. Objects with high albedos reflect a large fraction of incident radiation and appear bright in visible imagery. The albedo can be expressed as a non-dimensional number between 0 and 1 where 1 is a fully reflective object. It can also be expressed as a percentage where 100% is a fully reflective object. Conversely, a ratio of 0 or 0% indicates that an object is not reflective and would appear relatively dark or black in satellite imagery. Here's a list of albedos for common objects seen in satellite imagery.