There are two kinds of light: the glow that illuminates and the glare that obscures.
Light is the most complex phenomenon a compositor must understand. In other areas of digital production, elaborate models are derived to simulate the way light works in the physical world. Accurate modeling of the physics of light is crucial to a good 3D rendering program. The science of light phenomena, such as radiosity, caustics, the inverse square law, environment mapping, and many more, have transitioned from theoretical papers delivered at SIGGRAPH to features readily available in high-end 3D software.
The world ...