Indigo fabric has been produced with Indigo yarn dyed on the same way than the Indigo for Jeans. It has the same properties. One of the main indigo yarn used for knitwear is that the dye only affects the surface of the yarn and leaves the inside white, which allows to obtain unique effects of colour and contrast. The natural properties of indigo colours give low light resistance, dark shades of indigo are more light resistant. Static and long exposition of fabrics or garments to light should be avoided as well as to combustion gases or ozone.