Every trip through the washer removes more black dye and roughs up the surface, creating a fuzzy fade effect. Consumer Reports says, when you absolutely must wash, turn dark garments inside out to protect the surface, sort items by color and weight, and wash in cold water in the shortest cycle possible. Measure detergent carefully to avoid streaking and avoid bleach. Hang indoors to dry, laying sweaters flat on a lint-free towel. Dry cleaning your favorite dark items will keep the just-bought look a lot longer than laundering.
From:: Blacker blacks.