Specifies a color value. A color is always defined by a key value. What color is meant by this key value is defined by a standard reference systems (e.g. RAL).
For example if a RAL color should be expressed in the terms of the VEC the referenceSystem would be "RAL", the key would be the RAL number defined by the standard (e.g. "1003" for signal yellow).
Attributes of the type Color normally have the multiplicity [0..*]. This means that such an attribute can have a value for different referenceSystems (e.g. RAL, RGB,...). It must not have multiple values for the same ReferenceSystem.
The key of the color in the corresponding color reference system.
The identification of the color reference system, which is defining possible values and the semantic of color keys. (see KBLFRM-315)
On optional human readable description of the color (e.g. the name).