How does SKINLAB Colour Care work?
Your hair isn't a single color. In fact, many different tones blend together to give the final color that you can see. Blonde hair has a yellow base tone underneath the visible shade which gives it the depth it needs to form a natural looking shade. When your blonde dye begins to fade, this yellow base is revealed and your hair begins to turn brassy.
Colour Care shampoo is able to counteract brassiness and correct yellow hair through a simple matter of color theory. In the same way that you can mix different colors when painting in order to form new shades, the colors in your hair blend and form a new shade too. Violet is directly opposite to yellow on the color wheel, and colors that are opposite will neutralize each other when combined.
Due to this effect, the violet pigment in purple shampoo corrects yellow hair by cancelling out the appearance of the golden base color. Depending on how strong the toning effect of the particular purple shampoo is, this can help you maintain anything from a beige blonde to a silver blonde. How often you choose to use the product also affects this.