Adding bright rainbow colors to your hair is ideal for a theater production, a costume party, a look for Halloween, or just if you want to mix things up. A quick and simple method of doing this is to use watercolor paints with a thick paintbrush. It is a quick method, but the colors will not be as bold or last as long. If you have darker hair, using watercolors on your hair may be difficult as only certain colors show up.
Brush out the sections of hair you want to paint with the watercolors, and pin aside with a clip or bobby pins.
Dip the paint brush into water, then dip into the corresponding color you want for your hair. Rub the brush into the watercolor to make a thick base of color.
Take one of the sections of hair and hold it outwards. Use the brush to paint down the strands of hair until you achieve the color and brightness that you want. You will most likely have to dip the brush back into the paint several times, depending on the length, thickness and color of your hair .
Continue to hold out the section of hair you painted, than direct the blow dryer on a cool setting at the paint to dry it quickly and set it.
Repeat this procedure with all the other sections of hair you want to paint.
Wash with regular shampoo and water to remove when you are finished, rubbing the sections of hair you colored to ensure you get all the paint out.