yarn dye & why jeans fade

Published: 12-01-02

Here's a shot of a piece of warp yarn from a piece of denim. What you see here is that the yarn is deep blue on the outside and that it gradually fades towards the center. What happens when you repeatedly dip the yarn in indigo dye is that the cotton absorbs dye stuff but it does not become fully saturated, i.e. indigo blue through the entire yarn, because of the properties of the dye stuff combined with the tight spinning of the yarn. On the surface, you have a thick layer of indigo which is what you see on an unwashed pair of jeans. So, when you start wearing your jeans, the surface dye stuff will gradually fade away and as you wear through the jeans, lighter blue shades will become visible. Once you wear through the fabric, you'll see white cotton showing through.