when did indigo become a color of the rainbow
Indigo Isaac Newton introduced indigo as one of the seven base colors of his work. In the mid-1660s, when Newton bought a pair of prisms at a fair near Cambridge, the East India Company had begun importing indigo dye into England,[15] supplanting the homegrown woad as source of blue dye. In a pivotal experiment in the history of optics, the young Newton shone a narrow beam of sunlight through a prism to produce a rainbow-like band of colors on the wall. In describing this optical spectrum, Newton acknowledged that the spectrum had a continuum of colors, but named seven: "The originall or primary colours are Red, yellow, Green, Blew, & a violet purple; together with Orang, Indico, & an indefinite varietie of intermediate gradations."[16] He linked the seven prismatic colors to the seven notes of a western major scale,[17] as shown in his color wheel, with orange and indigo as the semitones. Having decided upon seven colors, he asked a friend to repeatedly divide up the spectrum that was projected from the prism onto the wall:
Over the Rainbow "Over the Rainbow" is a ballad, with music by Harold Arlen and lyrics by Yip Harburg.[1] It was written for the movie The Wizard of Oz and was sung by actress Judy Garland, in her starring role as Dorothy Gale.[1] It won the Academy Award for Best Original Song and became Garland's signature song, as well as one of the most enduring standards of the 20th century.