tips for keeping black color from fading after wash:
* When you wash them - don't dry them in a machine, hang them to dry, they stay dark much longer.
* Wash with cold water
* Before the first time you wash a new clothing item, presoak it in a vinegar solution. Take 1 cup of white vinegar and 1 gallon of cold water & soak the item. Let dry naturally and then launder as usual. The vinegar solution somehow locks the color and there is significantly less fading than normal.
* Add a thimble full of white vinegar to your wash. It'll preserve the color and it WON'T make your laundry smell sour/acidic. Just be sure to pair it w/the normal detergent u use.
* Wash them with detergent that does not have bleach in it.
recommended: woolite dark laundry

more fabric care tips from woolite:
http://woolite.com/care.shtml