CLC Outdoor & Landscape Lighting 3 — Questions and Answers
Question 1: What is 'light trespass' in the context of outdoor and landscape lighting?
- Light that attracts insects to a fixture
- Unwanted light spilling onto neighboring properties or the night sky (Correct answer)
- Light reflected off wet pavement
- A fixture's beam that hits a window at an angle
Correct answer: Unwanted light spilling onto neighboring properties or the night sky
Light trespass occurs when artificial light falls beyond the intended target area onto neighboring properties, roadways, or upward into the sky.
Question 2: When designing path lighting, what is the recommended maximum spacing-to-mounting-height ratio to ensure even illumination without dark spots?
- 10:1
- 6:1
- 4:1 (Correct answer)
- 2:1
Correct answer: 4:1
A maximum spacing-to-mounting-height ratio of 4:1 is commonly recommended to maintain uniform illumination along pathways.
Question 3: Which outdoor lighting technique is best used to make a sculpture or focal plant 'pop' against a dark background?
- Silhouetting (Correct answer)
- Shadowing
- Grazing
- Cross-lighting
Correct answer: Silhouetting
Silhouetting places the light source behind the object aimed at the background, creating a dark outline of the subject against a lit backdrop.
Question 4: For outdoor LED fixtures used in landscape applications, what minimum CRI is generally specified to render plant colors accurately?
- CRI 50
- CRI 70
- CRI 80 (Correct answer)
- CRI 95
Correct answer: CRI 80
A CRI of 80 or above is generally specified for landscape LED fixtures to ensure accurate and appealing color rendering of foliage and hardscape.
Question 5: A landscape designer wants to highlight a water feature at night without creating glare for seated guests nearby. Which fixture placement is most appropriate?
- Aim fixtures from outside the water toward the center
- Submerge fixtures inside the water feature aimed upward (Correct answer)
- Mount fixtures on tall poles above the water
- Place fixtures at eye level aimed horizontally across the water
Correct answer: Submerge fixtures inside the water feature aimed upward
Submerged underwater fixtures aimed upward illuminate water features from within while keeping the light source hidden below the water surface, eliminating direct glare.
Question 6: Which IES (Illuminating Engineering Society) full cutoff classification ensures that zero lumens are emitted above 90° (horizontal) from a fixture?
- Semi-cutoff
- Cutoff
- Full cutoff (Correct answer)
- Non-cutoff
Correct answer: Full cutoff
Full cutoff luminaires emit zero lumens at or above 90° from nadir and limit output above 80°, effectively eliminating uplight and reducing sky glow.
Question 7: What is the purpose of using a 'well light' (in-ground uplight) in landscape design?
- To provide general area illumination at ground level
- To uplight trees or architectural elements from a flush-mounted in-ground position (Correct answer)
- To illuminate underground utility markers
- To backlight water features from beneath the ground
Correct answer: To uplight trees or architectural elements from a flush-mounted in-ground position
Well lights are in-ground fixtures installed flush with the ground surface, used to uplight trees, columns, or architectural features while remaining concealed.
CLC Outdoor & Landscape Lighting 3
What is 'light trespass' in the context of outdoor and landscape lighting?