Fading, What is it?

[Giles]

There are plenty of misconceptions about fading. Here is a very simple 101, if you want me to expand on anything, then please ask.

Most “proper” indigo jeans are made with a warp that is rope dyed. In rope dyeing, the yarn strands are twisted very tightly together and moved through a series of vats filled with indigo solution. In between the vats the yarns are exposed to the air, whilst in the air, the indigo oxidises onto the surface of the yarn. The solution does not penetrate the centre of the tightly twisted yarns, leaving a white core. Typically the more baths of indigo, the yarns go through, the slower the fade (thicker layer of exidised indigo)

Fading is the abrasion of the oxidised indigo from the surface which exposes the inner white core.

Washing or soaking does not cause the denim to fade unless abrasion occurs in that process.

High-wear areas, are subject to more abrasion so lose the indigo coating quicker than low-wear areas. Take the rear pocket off a pair of highly faded jeans, and the indigo will be almost as-new.

The reason that some people think that washing causes the fades is that after a wash, the denim is clean, and dirt is no longer “hiding” the areas that the indigo has been abraded from the surface of the warp.

[Luijim78]

@Giles this is why once upon a time they washed jeans with stones to lighten them if I'm not mistaken

[Giles]

Yes, there were called stone-washed.....Horrible things

[scarfmace]

If I soak a brand new pair of jeans without friction and the water changes coulor, Is that because of the excess Indigo or is it possible that my jeans will come out a little lighter?

[Giles]

Excess indigo. They will come out a little lighter, but that excess indigo would falloff/be rubbed off very soon anyway. And the indigo loss will not really be noticeable and anyway, will make no difference to how they fade with use.

[endo]

how does natural indigo behave differently? is it more adherent to the yarn?

[Giles]

A lot of natural indigo yarns are not rope-dyed which results in different fading.

If rope-dyed, I am note sure if the oxidisation is stronger or weaker.

[cityofdelusion]

If I understand correctly, washing doesn't directly affect the contrast/quality of fades. In other words, a pair of jeans continues to fade no matter if you wash or not.

But could we say that, indirectly, washing decreases the contrast/quality of fades, i.e. washing contributes to the softening of denim and therefore to less abrasion being caused which then leads to fades becoming less contrasty?

[Giles]

Possibly. And, as I say, fading will occur if there is abrasion, so frequent washing will contribute to an overall lightening of the denim as washing is inherently abrasive..