The CIELAB System:
The Commission Internationale de l’Eclairage (CIE), the L*a*b* color space was modeled after a color-opponent theory stating that two colors cannot be red and green at the same time or yellow and blue at the same time.
The coordinates of CIELAB are L*a*b* but the color system is often informally referred to simply as L-a-b.
Defining and Communicating Color: CIE L*C*H* :
The L*C*h color space is similar to L*a*b*, but it describes color differently using cylindrical coordinates instead of rectangular coordinates.
Lightness: (L)
The luminous intensity of a color — i.e., its degree of lightness — is called its value. Colors can be classified as light or dark when comparing their value.
Hue : (H)
When asked to identify the color of an object, you’ll most likely speak first of its hue. Quite simply, hue is how we perceive an object’s color — red, orange, green, blue, etc.
Hue : (H)
Chroma : (C)
Chroma describes the brightness or dullness of a color — in other words, how close the color is to either gray or the pure hue. For example, think of the appearance of a tomato and a radish. The red of the tomato is vivid, while the radish appears duller.
Croma : (C)
Defining and Communicating Color: CIE L*C*H*
The L*C*h color space is similar to L*a*b*, but it describes color differently using cylindrical coordinates instead of rectangular coordinates.
CMC Report /Data Color Report :
Making decision on shade deviation %:
Metamerism :
A phenomenon exhibited by a pair of colors that match under one or more sets of illuminants (be they real or calculated), but not under all illuminants.
The substrate show different in different light source.
High Metameric Index High mean high metameric and metameric index low means low metameric.
Normally metameric Index < 0.5 = Acceptable ; Metameric Index > 0.5 = Not acceptable.