Purple conditioner uses crushed violet pigments to help purple shampoo combat yellow, brassy tones in dyed blonde hair. Blue conditioner hydrates and nourishes and works with Blue Crush Shampoo with crushed blue pigments to knock out orange tones in dyed brunette hair. On the color wheel, purple is the opposite of yellow and blue is the opposite of orange. Using these color opposites allows you to color correct your hair and neutralize warm tones.