Indigo

Indigo is a shade of blue, more specifically, purplish blue or dark blue.

Isaac Newton named and defined indigo as a spectrum color when he divided up the spectrum into the seven colors of the rainbow. The spectral range of indigo is between 450 and 420 nanometers.

The name of the color indigo originally came from the indigo plant. Indigo is a dye made from the indigo plant, used to dye cloth. Indigo dye also is used to dye denim cloth, which is used to make what are called blue jeans (they should really be called indigo jeans). This shade of indigo is called indigo dye.

The indigo plant originally came from the nation of India. The Ancient Greek language word for the dye is indikon. The Romans used the term indicum, which passed into Italian dialect and eventually into English as the word indigo.

These things are colored indigo:

• some grapes
• night sky in the mid-evening
• blueberries
• some small clams
• some eggplants
• Jenna Rose's jeans