The architecture of light: architectural lighting design concepts and techniques. A textbook of procedures and practices for the architect, interior designer and lighting designer pdfdrive com

FLAVORS OF DAYLIGHT
In order to visualize and implement the integration of daylight into design, it is helpful to categorize two types of daylight systems: Functional Daylight and Daylight Accenting.
Functional Daylight is the careful introduction of daylight into a space to serve task and spatial-defining functions. This is generally diffuse, even light that can accommodate long term visual comfort.
Figure 16.1 Controlling daylight through diffusion or shading (left) turns it into a tool for solving lighting challenges. Direct sunlight components (right) are useful for impact and interest.
Daylight Accenting is a more dramatic and obvious use of daylight to inspire certain moods and create distinct visual interest. These features may be integrated into high-design spaces where emotional impact is the priority.
These two types of daylight are accomplished through distinctly different types of systems and have very different effects on our environments. There are systems that introduce both simultaneously, but when we visualize a design effect, it is important to identify our target and distinguish between the two.
COMPONENTS OF DAYLIGHT (TEXTURES)
The other basic intuition that a designer should carry is the distinct difference in light quality that is obtained from the different components of daylight. Daylight enters our spaces in a number of different ways and takes on different texture accordingly. Just as we distinguish between the directional beam of an accent luminaire and the soft diffuse light of a glowing globe, we break down the components of daylight into three textures: Direct Sunlight, Skylight and Diffused Sunlight
Direct sunlight is, arguably, the least useful as a functional light source
and most hazardous to design. Light received directly from the sun is excessively bright and leads to situations of glare and unacceptable contrast. Direct sunlight can also introduce heat and UV radiation that can damage materials and fabrics. As creatures of reflected light, sunlight into our eyes or off of a bright surface into our eyes is simply too bright for our visual system.
Skylight is the product of sunlight diffusing and scattering through various states of our atmosphere. Skylight takes on many different qualities depending on time of day, time of year, weather and atmospheric conditions. From clear blue skylight to soft, diffuse cloudy daylight, most forms of skylight suit our visual system well as a sustained light quality for long durations. (This is no surprise, given our long history with skylight).