There're 3 main colors existing : brown, black and clear. But what if we have a client with red, pink or purple hair color? Or brown keratin is so dark for dark blonde hair? I'll teach how to create different colors of keratin, how to mix it and how to avoid yellow clear keratin on total blonde. Keratin matching is also important. Imagine you color extensions which perfectly match your clients color but keratin is much darker or lighter and bonds are very visible.