The Five DarkSky Principles in Landscape Lighting Design
1. Useful: Does the Light Serve a Purpose?
Every fixture should have a reason for being there.
For landscape lighting, that purpose might be:
- Illuminating a walkway or staircase
- Improving visibility around an entry
- Highlighting architectural features
- Accentuating specimen trees or landscaping
- Creating usable outdoor living areas
- Providing appropriate security or safety lighting
- Enhancing the appearance of a property after dark
A professional lighting design begins by identifying those objectives
rather than simply placing fixtures at regular intervals.
This is particularly important with residential landscape lighting. A
property can become overlit when fixtures are added without
considering what the existing lighting is already accomplishing.
2. Targeted: Put the Light Where It Belongs
Light trespass occurs when illumination extends
beyond the area where it is intended.
Targeted lighting minimizes unwanted illumination by carefully
selecting fixtures, optics, mounting locations, beam spreads,
shielding, and aiming angles.
For example, an architectural accent light should illuminate the
architectural feature, not the neighbor's property. A pathway
fixture should illuminate the walking surface rather than projecting
unnecessary light upward or outward.
Techniques such as:
- Proper fixture placement
- Shielding and glare control
- Narrow or appropriate beam spreads
- Careful aiming
- Appropriate mounting heights
- Downlighting
- Well lights and directional accent fixtures
- Low-profile landscape fixtures
can help create precise illumination.
This is where professional lighting design becomes especially
important.
Fixture selection and fixture placement are inseparable from the
quality of the final lighting result.
3. Low Level: More Lumens Don't Necessarily Mean Better Lighting
One of the most common misconceptions about outdoor lighting is that
brighter automatically means better.
It doesn't.
DarkSky recommends using the lowest light level necessary to
accomplish the intended purpose.
Professional landscape lighting relies on techniques such as
layering, contrast, beam control, spacing, and selective
illumination
rather than simply increasing fixture output.
For example, a specimen tree may require surprisingly little light to
become a dramatic focal point when the fixture is properly positioned
and aimed.
Similarly, a pathway can be comfortable to navigate without being
illuminated as brightly as a commercial parking lot.
The goal is not to eliminate useful illumination. The goal is to
eliminate unnecessary illumination.
4. Controlled: Light Only When It's Needed
A DarkSky-conscious lighting design considers not only
where light is used, but also
when it is used.
Modern low-voltage outdoor lighting systems can incorporate
sophisticated controls, including:
- Astronomical timers
- Photocells
- Dimmers
- Smart lighting controls
- Zoning
- Scheduling
- Motion or occupancy sensors for appropriate applications
These controls allow different portions of a property to operate
according to their intended use.
For example, entertainment areas may operate at one level during the
evening and dim later at night. Security lighting may activate only
when movement is detected. Architectural lighting can be programmed to
turn off at a predetermined time.
This approach reduces unnecessary energy consumption while helping
minimize the amount of artificial light introduced into the nighttime
environment.
5. Warm-Colored: Choosing the Right Color Temperature
Correlated color temperature (CCT) is another
important consideration in responsible outdoor lighting.
CCT is measured in Kelvin (K). Lower Kelvin values generally produce
warmer, more amber-colored light, while higher values produce cooler,
bluer-looking light.
DarkSky International recommends warmer-color lighting where possible
and identifies concerns associated with blue-rich light, including
increased atmospheric scattering and potential impacts on wildlife.
For residential landscape lighting, warmer CCT options can also create
a more natural and inviting appearance.
Rather than washing an entire landscape in cool white light, a
professional lighting designer can use warm-color sources
strategically to complement:
- Stone
- Brick
- Wood
- Natural landscaping
- Water features
- Architectural finishes
- Mature trees and vegetation
The result can be a lighting system that feels integrated with the
property and its surroundings.
