You can determine whether a person is in the warm or cool category by the person's skin and hair color. Holding a white sheet of paper next to a client's skin often helps determine if the client has a warm or cool skin tone, as the white paper serves as a base of comparison. Knowing a client's skin tone is important in make-up design in order to choose colors that complement a client's natural coloring.

Salon Fundamentals Esthetics (p. 421)