Whether you want to dye your hair for a special occasion or simply try out a new color for a while, you can change your color temporarily with semi-permanent dyes. These dyes lack the harsh chemicals found in permanent hair dyes, making them the healthier choice for your delicate strands. Although semi-permanent colors normally last six to 12 shampoos, you can extend the life of your color by taking advantage of a few maintenance tricks.
Leave the dye in for an extended period of time. Since semi-permanent dyes contain pigments and lack bleaching agents like ammonia and peroxide, they are safe to leave in for extended durations. You can wrap your hair in a plastic cap and sleep with the dye in your hair overnight, if you like. Before leaving your dye in for long periods, however, check the label to ensure it is semi-permanent and does not contain ammonia or peroxide.
Rinse your hair in cold water. Hot water will lift more pigment than cold water.
Soak your hair in white vinegar immediately after rinsing. Pour enough vinegar on your hair to soak each strand. Vinegar raises the pH levels of your hair and helps the color stay longer.
Limit the number of times you shampoo your hair. Boxes of semi-permanent dye usually indicate the number of shampoos the color will last. This is because each time you shampoo your hair, you wash out a bit of the pigment. Although you should wash your hair whenever it is dirty, try to wait as long as possible between shampoos. Wear a shower cap, if you want to bathe without washing your hair.
Deep condition your hair every time you shampoo. Conditioners lock the color within your strands. If you are shopping for a new shampoo or conditioner, opt for varieties designed for color-treated hair.
Add 1 tbsp. of dye to your shampoo and conditioner, and shake the bottles well to fully combine the mixtures. Each time you use these colored products, you refresh your color and fight the fading effects of washing.