You can refresh your black clothes by adding bluing, or strong coffee, or tea (2 cups) to the rinse water. Although I prefer the bluing (found in the laundry section of most stores) to Grandmas old fashioned method of coffee or tea…I prefer to drink my coffee. Actually with two young kids and a full-time job I NEED to drink my coffee!
They should return to their original dark black state. To prevent future fading, wash them in cold water, with Ivory Flakes plus only a small amount of detergent.