Using a demi-permanent hair color gradually covers gray hair and minimizes the grow-out line. The necessary materials are the color in a shade similar to the natural shade, developer, an applicator bottle, a shower cap and gloves. Timing is 30 minutes in addition to the application time.
Wash and dry the hair
Demi-permanent hair color does not penetrate as deeply as permanent color, so it works best on clean, dry hair. Condition the ends if they are especially porous.
Measure the color
Follow the manufacturer's instructions for mixing, but the ratio is typically 1 part developer to 1 part color. Use an applicator bottle with measure marks for best results. Use gloves when working with the chemicals.
Mix the color
Squeeze out some of the air from the bottle, and cover the tip with your finger. Shake the bottle vigorously until the solution is completely mixed.
Apply the color
Start with the perimeter, making sure the hairline is covered. Apply the color from roots to ends in a methodical manner. Starting with a part down the middle, work down one side, then the other. Finish by working the color down the back of your head. If the ends of the hair are very porous, don't cover them in color until the final 10 minutes.
Time the coloring
Cover your head with a shower cap, and let the color stay on your hair for 30 minutes, or according to manufacturer instructions.
Rinse out the color
Using cool water, rinse the hair until the water runs clear. Shampoo, condition, and style as usual.