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

Very Directional Light
At the directional end of the spectrum, we have reflector driven lamps like halogen MR lamps that have precision engineered reflectors that drive light out. This light is perfect for accenting art and decorative objects, but creates glare and contrast that may be unsuitable for lighting a social gathering space. We can also create this directional light with accent luminaires that have precise reflectors around a small halogen or HID source. Many LED sources also provide very directional light. We can compare this light to the harshness of direct sunlight.
Figure 9.5 Effects of very directional light (left) are often the product of lamps and luminaires that incorporate engineered reflectors and small sources (right).
Directional Light
Slightly-softer directional light can be created with PAR type lamps. These lamps also have a reflector, but incorporate diffusing lenses and less-precise optics that create a slightly more diffuse quality of light. PAR lamps are built around small Halogen or HID sources. We can also create this quality of light by placing diffusing filters in front of MR type lamps. This light is perfectly functional for painting light onto art, gathering areas and architectural features; it is acceptable to some for creating even levels of task light. It is similar to the quality of unfiltered skylight.
Figure 9.6 Effects of directional light (left) are often the product of lamps or luminaires that incorporate less precise optics and reflectors.
Diffuse Light
Towards the softer end of the spectrum are luminaires that use reflectors to harness the light of diffuse lamps. When we take an otherwise diffuse incandescent lamp or fluorescent lamp and build a large reflector around it, the product is a subtle wash or pool of slightly diffuse light. We also get this light from our family of incandescent “R” lamps that are little more than a common light bulb with a generic reflecting surface built into the back. Diffuse light is unsuited for making an accent statement, but delivers a nice quality of light for gathering areas and task situations. We might liken this effect to the soft light of daylight diffused through sheer curtains.
Figure 9.7 The effects of diffuse light (left) are often the product of diffuse lamps (right) and luminaires
with engineered reflectors and larger sources (right).
Very Diffuse
On the very diffuse end of the spectrum, we consider glowing sources that put out light in every direction and often include diffusing materials to encourage the spread of light. We get this light from bare incandescent and fluorescent lamps.
We also create this light with diffusing sources like shaded table lamps, floor
lamps, diffusing pendants and sconces. This is like the light we get on a cloudy, overcast gray day. Diffuse light is suitable for filling an entire room with a homogenous glow, but is certainly not useful for accenting objects.
Figure 9.8 Effects of very diffuse light (left) are often the product of luminaires with diffusers and diffuse sources (right).
With these four textures committed to our intuitive knowledge base, a designer is well-prepared to articulate the quality of light envisioned for a space. Once you get used to the idea of making a texture decision about light, you will wonder how you ever got by without doing so. The designer who can visualize and describe different textures of diffuse and directional light can also identify light sources, lamps and luminaires that are not going to meet the needs of the design.