Important Materials Theory - Photographic Rendering with V-Ray for SketchUp - page 246

global illumination start to interact with the material properties in the scene. Keep-
ing a material's reflectance property below the recommended 80 percent mark can
be accomplished by making certain that the Value parameter (as in Hue, Saturation,
and Value) is always set at 204 or below.
Note
In the case of certain special material types, this can climb to a value of around
about 218, which would give us a reflectance value of about 85 percent.
The end result of all this care and attention will of course be the creation of materials
in our scenes having color components that look and behave in a very realistic man-
ner, thus making it that much more likely that we will be able to create a genuinely
photographic final render.