| http://www.w3.org/ns/prov#value | - Following the ASTM Book of Standards E 284 ???Standard Terminology of Appearance??? [15], opacity is the ability of a thin film or sheet of material, such as paint or paper, to hide a surface behind and in contact with it, expressed as the ratio of the reflectance factor when the material is backed by a black surface to the reflectance factor when it is backed by a white surface (usually having a
|
