What Does Indigo (Color) Mean?
Indigo is a spectral color between blue and violet at about 420 to 450 nanometers (nm) in wavelength.Today’s color scientists do not often recognize indigo as a separate color division and place it between blue and violet.
Techopedia Explains Indigo (Color)
Any wavelength of less than 450 nm is simply referred to as violet. Here are the color frequency wavelengths:
