There are two different types of this pigment: black and brown. The smaller amount of brown one has, the lighter or more ashen blond the hair will be. In turn, the higher the amount of brown, the darker or more brown the hair will be. As for black eumelanin, in high quantities, it's what makes the hair black. But in lower levels, it's responsible for causing the hair to become gray. So now you can dazzle your friends, giving them their own custom "hair reading," all thanks to your expert hair color knowledge.