Landscape Design Landscape Lighting Design 2 — Questions and Answers
Question 1: What is 'grazing' in landscape lighting design?
- Installing lights at pasture-level for rural properties
- Placing a light source very close to a wall or textured surface to highlight its surface relief and texture (Correct answer)
- Using wide-beam floodlights to illuminate large open lawn areas
- Lighting a garden at a low angle from the perimeter inward
Correct answer: Placing a light source very close to a wall or textured surface to highlight its surface relief and texture
Grazing involves positioning a fixture very close to and parallel with a textured surface (brick, stone, bark) so the raking light highlights the surface relief and three-dimensional texture.
Question 2: What is 'beam spread' in landscape lighting fixture selection?
- The total wiring distance a transformer can support
- The angle of the light cone emitted by a fixture, ranging from narrow spot to wide flood (Correct answer)
- The reach of a motion sensor around a security light
- The coverage area of a path light at a given height
Correct answer: The angle of the light cone emitted by a fixture, ranging from narrow spot to wide flood
Beam spread describes the angle of the light cone produced by a fixture — narrow spots (10–15°) concentrate light on a focal point while wide floods (45–120°) wash a broader area.
Question 3: What does CRI (Color Rendering Index) measure in landscape lighting?
- The cost-to-return ratio of LED fixtures vs. halogen
- How accurately a light source renders colors compared to natural daylight on a 0–100 scale (Correct answer)
- The calibrated reduction in light output over the fixture's rated lifespan
- The corrosion resistance rating of outdoor fixture housing
Correct answer: How accurately a light source renders colors compared to natural daylight on a 0–100 scale
CRI measures how accurately a light source renders the true colors of objects compared to a reference natural light source, with 90+ CRI recommended for landscape applications where plant and material color accuracy matters.
Question 4: What is 'silhouetting' as a landscape lighting technique?
- Using dark-colored fixtures that blend into the landscape at night
- Placing a light source behind a plant or object to create a dramatic dark silhouette against a lit wall or surface (Correct answer)
- Outlining a structure's roofline with decorative string lights
- Creating a shadow pattern using laser light projectors
Correct answer: Placing a light source behind a plant or object to create a dramatic dark silhouette against a lit wall or surface
Silhouetting places a light source behind a plant or object aimed at a wall or surface, creating a striking dark silhouette of the subject against the illuminated background.
Question 5: What is the purpose of a 'photocell' or 'dusk-to-dawn' sensor in landscape lighting control?
- To measure the color temperature of fixtures and adjust accordingly
- To automatically turn lights on at dusk and off at dawn based on ambient light levels (Correct answer)
- To dim lights proportionally based on the phase of the moon
- To prevent circuit overloading when multiple fixtures activate simultaneously
Correct answer: To automatically turn lights on at dusk and off at dawn based on ambient light levels
A photocell sensor detects ambient light levels to automatically turn landscape lights on at dusk and off at dawn, providing convenient, energy-efficient operation without a timer.
Question 6: What is 'voltage drop' in a low-voltage landscape lighting system and how is it addressed?
- The dimming of lights over time as bulbs age; addressed by replacing bulbs on schedule
- The reduction in voltage along a wire run as current travels farther from the transformer, causing lights to dim; addressed by using larger wire gauge or multiple runs (Correct answer)
- The drop in fixture height as stakes settle into soil over time; addressed by reinstalling fixtures seasonally
- A decrease in system voltage during peak demand hours from the utility; addressed by adding a voltage stabilizer
Correct answer: The reduction in voltage along a wire run as current travels farther from the transformer, causing lights to dim; addressed by using larger wire gauge or multiple runs
Voltage drop occurs because wire resistance causes voltage to decrease as current travels along longer wire runs, resulting in dimmer fixtures farther from the transformer; corrected by using larger wire gauge or home-run wiring configurations.
Landscape Design Landscape Lighting Design 2
What is 'grazing' in landscape lighting design?