Value can be referred to as the element of shadow. Value deals with the lightness or darkness of a colour. Our brain understands objects by the way they reflect light, also indicating how dark or light they are. Value deals with light, we see things because light reflects off of objects and goes into our eyes. Our mind processes the light and nationalises what we are seeing. In order to draw or paint in a way that creates the illusion of what we normally see, we must fully understand light and how it reacts on surfaces. Value is the key to light.