Red and Green as Equivalent Colors?

Whichever mnemonic you learned to help remember the colors of the rainbow -- Roy G Biv, Richard of York Gave Battle in Vain, Run Off Young Girls Boys in View -- I bet one thing was never questioned and that was that there were seven colors. We've Isaac Newton (and beliefs concerning the number seven) to thank for Red, Orange, Yellow, Green, Blue, Indigo, and Violet. But did you know the Ancient Greeks had a totally different spectrum?

"The Greeks saw... white at one end and black at the other -- or more properly, light and dark. All the colours lay along the scale between these two extremes, being admixtures of light and dark in different degrees. ... Red and green were both considered median colours, midway between light and dark -- and so in some sense equivalent.

"The reliance of medieval scholars on Classical Greek texts ensured that this colour scale was perpetuated for centuries ... In the tenth century AD, the monk Heracluius still classified all colours as black, white and 'intermediate'.

"... [blue] was seen as a variant of black, and Greek terms for the two overlap. ...there are no culture-independent concepts of basic colors."

-- Quote Source: Philip Ball, Bright Earth, p15/6.

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