Light, or its absence, represents a substantial issue in architecture. Its presence is essential to define the space; natural light in particular, "soft" and continuous, has this task. Natural light design aims to minimize the energy consumption of buildings and maximize well-being in confined spaces. It is an element of improvement of comfort conditions. The variability of natural light during the day is a positive stimulus both from the biological and psychological point of view for the human being and work environments lit by natural light are considered much less stressful for the eyes. In addition to that, when a workplace is exposed to natural light it makes it more productive, more efficient, healthier and more creative.