Jeans manufacturers make denim bluer with indigo dye.

The visible colors of the rainbow are red, orange, yellow, green, blue, indigo, and violet.

Indigo blue is one of Japan's traditional colours.

I can't remove the indigo dye in my hair!

A rainbow consists of red, orange, yellow, green, blue, indigo and violet.

I'm not able to remove the indigo dye in my hair!

I had never seen an indigo bunting until I moved here.