This paper wants to contribute to the development of a novel methodology in which daylight and artificial light are combined in the definition of the user's experience of architectural space. This experience is based upon the three systems that are triggered by light, visual, biological and perceptual/psychological. Natural Light is an attempt to deal with the issue of quality in spaces under a human perspective. This paper resumes the theoretical question that is leading a PhD research work, the result of a workshop developed in the city of Stockholm and the practical and methodological applications that will follow.