Track lighting, a light source is an object that emits light. Sources can be primary or secondary. The main produce their light (sun), the secondary reflected light from other sources (the Moon). In turn, they can distinguish between primary, natural resources (sun) and artificial (lamp).
A light source may spread or timely. Diffuse lights falling on the object from different directions, giving less sharp shadows darker the farther an object surface. Points of light coming from distant objects is reduced from point lights, able to speak more or less similar directionality between the rays emitted, a track lighting create an object casts a shadow over sharp or cutting and become greater the closer the object and the light source further from the screen shaded are.
Special mention must sunlight because of the distance that separates the Sun from Earth, has a strong directionality, but also a source of light is significantly larger than the size of a terrestrial object corresponding to the track lighting. Its ray’s incident at a point on the Earth with the opening of about thirty-two dispersion, causing the shadow of any object goes completely faded to place it at a distance of more than a hundred headed point forty times its size relative horizontal direction to the surface. Diffuser attached atmospheric gases and suspended as water vapor, especially in the form of clouds, sun exposure can vary from timeliness thirty two dispersion nearly one hundred eighty dispersion on the surface, or even more at a certain distance from it.