Use the Best Shampoo on Color_Treated Hair : When you wash color_treated hair, be sure to use a color_protecting shampoo. Using a good shampoo will help your color last longer and help maintain the health of your processed hair. Avoid Sulfates on Color_Treated Hair : Sulfates can strip color from hair, so look for a sulfate_free shampoo. Sulfates contain salt, which strip away moisture, and moisture loss is one of the main causes of color fading. Use Clarifying Shampoos on Color_Treated Hair Only Before Coloring : Clarifying shampoos can strip hair color because contain a high level of detergent in order to deep cleanse and remove build_up of dirt and hairstyling products, so avoid using them unless it’s right before you are going to have your hair colored. If you have gray hair you are covering, look for a clarifying shampoo that removes hairspray resins, silicones and waxes.
Buy two boxes. If your hair is past your shoulders, or shoulder length and extremely coarse, use two boxes of the same shade to ensure full coverage. Just make sure to mix the dyes in a glass or plastic bowl a metal one will oxidize the dye and cause it to change color. Consider your hair texture : Hair texture matters just as much when dyeing your hair as it does when cutting it. "Coarse, curly, frizzy, or unruly hair sucks up color faster and will become cooler_toned when you dye it, so it will look ashier, or slightly bluish," says Ionato. "Fine to medium hair textures don't absorb color as easily and will become a slightly warmer tone when you add dye, meaning it will have orange, red, or copper undertones." So what does that mean for you when you're standing in the aisle at the drugstore? If your hair is frizzy or curly, pick a color that's warm (golden, copper, bronze), but a little lighter than your natural hair color; if your hair is fine and straight, choose cooler shades (champagne, beige) that are slightly darker than your natural color.