a pressure - sensitive copying material which employs a color - producing substance and a color substance - accepting material is disclosed . the color substance - accepting material contains , as reaction components , a chloride of a metal having an atomic weight of from 50 - 66 , together with a urea or its derivatives and a binding agent . the color - producing substance includes a dyestuff which is combined with the binding agent and reacts with the color substance - accepting material during color formation .