Indigo is a controversial color. It is blue but not quite. And also violet, but not quite. The great Sir Isaac Newton himself introduced indigo as one of the seven colors in his spectrum. But more than a century later, its place in the spectrum was challenged by another Isaac–the science fiction author and biochemistry professor Isaac Asimov–who pointed out that “It is customary to list indigo as a color lying between blue and violet, but it has never seemed to me that indigo is worth the dignity of being considered a separate color. To my eyes it seems merely deep blue.”
To my eyes, indigo is indeed deep blue. But it is also deep violet. It can be one color. Or many, depending on how one looks at it.
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