It's not uncommon for colored clothes to fade in the washer. Dye is often released from the fabric during the wash cycle, which not only alters the color of the garment, but can also bleed onto other items in the washer. Use vinegar in the washing machine to set in the color of the fabric so it no longer fades or bleeds.
Set your washer to the smallest water level with cold water. Add 2 cups of white vinegar.
Put the clothing in the washer so it's completely submerged in the vinegar and water solution. Let it soak for a few hours.
Turn on the washer and run the wash cycle without adding any detergent. Let the washer run a completely wash and rinse cycle. Dry the clothing as you normally would.
Add 1 cup of white vinegar to the rinse cycle for each subsequent washing. This will help your clothes to retain their color.