Sometimes books contain descriptions of oils that are thought to be dyes. However, experience shows that the oil included in such potions becomes a barrier between the hair and the special powers of the potions, so that these powers do not penetrate the hair and have no effect unless they have great power or a powerful special property. But great power can be expected only from things that have significant coloring power, such as, for example, iron rust, lead rust and the watery part of nut shells, it is possible that when the forces of these and similar substances are concentrated in oils, and the forces of conducting drugs, for example, vinegar or wine will mediate, some coloring will take place. I see and hear that people testify to the reliability of the statement that if you cut off the root of a walnut tree in early spring, insert it into a bottle of oil and bury both in the ground, the nut root will absorb the contents of the bottle, drawing in and sucking it in, and in the fall again will release and return a significant part of it to the bottle, and the oil will turn into paint. Most of the remedies that help and have an effect in this case produce such an effect only due to their concentration.
There are three types of dyes used to dye hair; they make it black, light brown or light. We'll start by mentioning some good blackening agents.