In general, you should only about 20 more minutes. However for stubborn gray hair, this could take up to 45 minutes.
You can also put on a cape or smock to help protect your clothes or give your skin an extra layer of protection. These are available from most beauty supplies stores.
If you have long or thick locks, try separating your hair into four sections before coloring. This give you more control while you color, and a more even rinse afterwards.
Once the conditioner has set, rinse it out using cool water. This helps close the cuticle of the hair, keeping it soft and shiny longer.
