RE: How to mix color and developer for a home touch up
What should the ratio be of color to developer for a home touch up? Mix equal parts color to developer. Is the remaining unmixed product okay for a couple of weeks afterward? Whatever color you do not mix with developer may be saved for the following month's application or stored for up to a year. Once you mix color and developer, you must use it immediately. Any advice on resistant gray at the facial hairline? Use full strength (equal parts color to developer) on gray, and process for 45 minutes. Use a cap and heat for the first 5 minutes.
