What color is indigo?

Indigo is blue-purple, darker than purple, but redder than blue, which can be divided into blue and purple.

Indigo is a color with the frequency of 670~7 10THz (corresponding to the wavelength of 450~420nm in the air), which is between blue and purple. It belongs to the high-frequency part of electromagnetic wave visible light, and its frequency is second only to purple, which generally refers to blue-purple between blue and purple, and belongs to the common color system.

Indigo dye color

A color different from spectral indigo or pigment indigo. The first two tend to be purple, and indigo dye is pure navy blue (navy blue) without purple. In fact, this is a dye extracted from Polygonum cuspidatum or Indigofera, that is, the "green" in Xunzi's "Encouraging Learning" is "green, taken from blue, and green is blue". The color of the finished dye is relatively dark, close to the color of the web page-midnight blue.

As long as about 55% cyan and 45% magenta are mixed, the pigment indigo can be transferred.

By comparing the two different trichromatic diagrams of additive and subtractive colors, we can distinguish mesh indigo from pigment indigo. The former displays different proportions of light in each pixel of the computer screen in an additive way, while the latter displays it in a subtractive way by using pigment mixing. The screen indigo produced by adding color is brighter because it is produced by light instead of pigment.