Semiotcs of Color
Colors and how they can express coded information is an area often focused on in field of design, art, physiology and philosophy. Easily identified iconography in conjunction with color can quickly inform us about potential dangers (warning=yellow, danger=red), it can guide us on what social expectations are, and easily identify product branding (Mc Donald's, Coke, etc...).
The most common colors have a standard social precept in which specific colors might stand for a general mood or idea. These meanings do not often transcend the boundary of the society that has constructed the meaning. An example is the color black, which often stands for death in western society while its opposite, white, is used to symbolize death in the eastern cultures.
There have been systems put in place in the past that use colors to signify abstract meaning. These systems range from those used in coat of arms, flags, and military uniforms to the color and patterned Setts of Scottish kilts used to identify clans or groups.
The Incas are believed to have used a system of colored strings and knots as a system of writing and recording data which was probably one of the first uses of mapping color directly to language. (http://www.ee.ryerson.ca/~elf/abacus/inca-khipu.html).
In modern times, electronic engineers are using color mapping system developed for identifying the resistance of resistors (10 colors that represent the individual numbers from 0-9) as well as color coding for wires (http://en.wikipedia.org/wiki/Electronic_color_code).