Important Materials Theory - Photographic Rendering with V-Ray for SketchUp - page 240

wavelengths are being reflected. A reflectance value typically equates to
what we would call the brightness of an object's surface color.
• Transmittance : This measures the ability of real-world materials such as
glass to let light pass through rather than bounce off their surface. Where a
high level of transmittance occurs, we typically find a complete absence of
surface color information due to the fact that no reflection of any of the com-
ponent wavelengths of light has occurred. This is why clear glass is only vis-
ible due to its specular reflection as well as its refractive properties.