The measurement of color is a young science, and is recognized as part of a larger field of study known as appearance science. Appearance can be defined as the phase of visual experience by which things are recognized. There are several appearance modes to identify the situation when a light source or object is recognized. The object mode encountered daily is the most familiar mode. It consists of a person observing an object illuminated by a light source. People make appearance judgments all day long without being aware of how an object is easily recognized as dull or glossy, transparent or opaque. Appearance technology classifies objects based on their based on their distribution of incident light. Appearance attributes can be divided into two main categories-those related either to spectral (color) or to geometric (spatial) light distribution