CLD Lighting Design Principles & Techniques 2 — Questions and Answers
Question 1: Which lighting technique uses a light source placed close to and parallel to a wall surface to emphasize texture?
- Grazing (Correct answer)
- Wallwashing
- Uplighting
- Backlighting
Correct answer: Grazing
Grazing places the fixture very close to the surface at a steep angle, creating shadows that reveal texture and surface relief.
Question 2: What is the primary purpose of a photometric report in lighting design?
- To document fixture costs
- To predict light distribution, intensity, and quantity in a space (Correct answer)
- To specify lamp color rendering index only
- To outline the electrical load schedule
Correct answer: To predict light distribution, intensity, and quantity in a space
A photometric report uses manufacturer IES data to model and predict how light will distribute, illuminance levels, and uniformity ratios in a space.
Question 3: In the Munsell color system, what does 'chroma' specifically describe?
- The lightness or darkness of a color
- The saturation or purity of a color (Correct answer)
- The dominant wavelength of a color
- The reflectance value of a surface
Correct answer: The saturation or purity of a color
Chroma in the Munsell system measures the degree of departure from neutral gray, representing color saturation or purity.
Question 4: What is 'sparkle' as an intentional lighting design technique?
- Excessive glare from bare lamps
- Small, intense points of high luminance that create visual excitement (Correct answer)
- Flickering caused by voltage instability
- Light bouncing off metallic HVAC ducts
Correct answer: Small, intense points of high luminance that create visual excitement
Sparkle is the deliberate use of small, bright pinpoints of light — such as from faceted crystals or narrow-beam LEDs — to add visual energy and interest.
Question 5: A designer specifies a luminaire with a beam angle of 15° for accent lighting. What effect does this produce compared to a 40° beam?
- A wider, more diffuse pool of light with lower center intensity
- A narrower, more concentrated pool with higher center intensity (Correct answer)
- Identical footprint but higher overall lumens
- Broader coverage but increased glare
Correct answer: A narrower, more concentrated pool with higher center intensity
A 15° beam angle concentrates light in a smaller, tighter circle with higher center beam candlepower, ideal for highlighting specific objects.
Question 6: Which principle explains why a room with dark walls requires more lumens to achieve the same perceived brightness as a room with light walls?
- The inverse square law
- Surface reflectance and interreflection (Correct answer)
- Purkinje shift
- Luminance adaptation
Correct answer: Surface reflectance and interreflection
Dark surfaces absorb light and reduce interreflection, so more initial lumens are needed to achieve the same illuminance level as a room with high-reflectance surfaces.
Question 7: In daylighting design, what is the 'daylight factor'?
- The ratio of exterior luminance to solar irradiance
- The ratio of interior illuminance at a point to simultaneous unobstructed exterior horizontal illuminance (Correct answer)
- The percentage of window area relative to floor area
- The thermal gain coefficient of glazing systems
Correct answer: The ratio of interior illuminance at a point to simultaneous unobstructed exterior horizontal illuminance
The daylight factor (DF) is a dimensionless ratio comparing indoor illuminance at a specific point to simultaneous outdoor illuminance under overcast sky conditions.
CLD Lighting Design Principles & Techniques 2
Which lighting technique uses a light source placed close to and parallel to a wall surface to emphasize texture?