About Cotton - it's not white

[rabbithorns]

It's not white. Not right out of the boll. It's a variant of light green, tan, or yellow. It's always bleached if the cotton fabric is white.

So please don't think you have to find the magic cure for dingy white clothing. Either you bleach it (somehow) or you don't. And even with bleaching, the cotton will eventually break down enough that it will revert to its natural color, which we call "dingy."

[JTA Mom]

It can't 'revert' back because it is no longer alive. It's like bleaching hair. Once bleached, there's no reverting back to anything. Bleaching makes cotton (& hair) porous, so it's much more likely to pick up colors from the environment, like minerals in water, soap buildup, etc.

And cotton is bleached when it's white or colored. Unless it says unbleached cotton, it's bleached. Regular (unbleached) cotton is difficult to dye because, like you said, the underlying natural color influences the end color in dying. So a tan dyed green will look different than a yellow cotton dyed green.

Ami

[rabbithorns]

By "revert" I only mean the white is not the natural color and since the fiber is now stripped and the hairs opened, it will take on natural oils as it did when it was alive and change color. This makes it look darker and looks like it has reverted to its natural color. You're right that it doesn't technically revert. But that's often how I've read it when that process has been described.