The simplest definition of light is “visually perceived radiant energy.” “Visible” light is just a small segment of the electromagnetic spectrum- a broad range of radiant energy which also includes X-ray, ultra violent and infrared energy, micro-waves and radio waves. Any form of electromagnetic energy, including light, radiates outward from its source in straight lines at “the speed of light” (300,000 kilometers per second) and dissipates as it gets further from its source.
As visually perceived radiant energy, light powers the mechanism of sight. It is light, reflected from objects to our eyes, that allows us to see. Of all our senses, sights the most dominant, controlling and defining how people perceive the world. And yet its impossible to prove that any two people see a given object in exactly the same way. In fact it often seems that visual perception-an individual’s response to light-is extremely subjective. This makes it difficult to define and measure specific attributes of light. Furthermore, changes in light can changes in light change people’s perceptions. A dark alley, for example, provokes an entirely different reaction than one that is brightly lit. lighting, therefore, can have a profound effect on people’s emotions and how they respond to the enviorment.
