Jeans Care - Preserve Jeans Color
Most jeans aren't cheap and you want them to last as long as possible. Even if they were cheap, if they fit you good, they're priceless. You want to keep them looking as good as possible for as long as possible. Preserving the color of your jeans is critical in prolonging the life of your jeans.
How To Preserve The Color Of Your Jeans:
Wash your jeans inside out. The temperature you wash your jeans in is not nearly as important as turning them inside out. The action of the washing machine's agitator is destructive to both the fabric's fibers and dye. Turning jeans inside out is the most important thing you can do to preserve the color of your jeans.
If your jeans aren't too soiled and your washing machine has a gentle cycle, use it. Same with with the dryer, or better yet, air dry them.
Some people swear by a vinegar soak before washing their jeans for the first time to preserve the color of jeans. This method only works if the jeans have not been washed previously -
new jeans only. Use a 3 to 1 ratio, 3 parts water to one part vinegar. (Some people say this won't help, but it definitely won't hurt your jeans either). I've tried it, but I haven't bought two identical pairs of jeans and tested it.
Dry cleaning your jeans is another method of preserving your jeans. Obviously it is an expensive option, most likely reserved for expensive jeans that are not in need of frequent washings.
If they are really dark jeans you can use the new detergents that are for darker colored clothes. There are at least a couple of different ones available and I haven't tested them. I would assume they would do an excellent job of preserving the color of darker jeans since that's what they were specifically made for.