CCE Lighting & Material Interactions 3 — Questions and Answers
Question 1: A textile designer notices that a carpet sample looks greener on the showroom floor than in the client's home. The most likely cause is:
- The carpet compressed differently underfoot at the showroom
- Different light sources in each environment causing a metameric shift (Correct answer)
- The client's eyes adapted to the home environment permanently
- Carpet dyes oxidize when removed from the showroom
Correct answer: Different light sources in each environment causing a metameric shift
Showroom and residential light sources often differ in spectral power distribution, causing metameric colors to shift in appearance.
Question 2: Subsurface scattering is most relevant when predicting the color appearance of:
- Polished metal surfaces
- Translucent materials like marble, skin, or wax (Correct answer)
- Flat matte painted drywall
- Mirror-finish laminates
Correct answer: Translucent materials like marble, skin, or wax
Subsurface scattering occurs when light penetrates a material, scatters within it, and exits at a different point, creating the characteristic glow of translucent materials.
Question 3: In the context of color-critical work environments, D50 is preferred over D65 as a viewing standard primarily because:
- D50 is brighter and reduces eye strain
- D50 more closely matches the color temperature of typical indoor printing environments (Correct answer)
- D50 has a higher CRI than D65
- D50 eliminates metamerism entirely
Correct answer: D50 more closely matches the color temperature of typical indoor printing environments
D50 (5000K) is the ISO standard for graphic arts viewing because it better matches the typical interior ambient light under which printed material is evaluated.
Question 4: A glossy red tile and a matte red tile with the same colorant appear to have different saturations in bright sunlight. The glossy tile appears:
- More saturated across all viewing angles
- Less saturated than the matte tile due to specular highlights washing out the hue (Correct answer)
- Identical to the matte tile in all lighting
- Darker and more neutral than the matte tile
Correct answer: Less saturated than the matte tile due to specular highlights washing out the hue
Specular highlights on glossy surfaces are near-white and reduce the apparent chroma/saturation of the color, especially under direct bright light.
Question 5: Iridescence in butterfly wings and some coatings is caused by:
- High concentrations of fluorescent pigments
- Thin-film interference where light waves reflect off multiple layers and interact constructively or destructively (Correct answer)
- Birefringence in crystalline pigment structures
- Phosphorescence from UV-charged surface molecules
Correct answer: Thin-film interference where light waves reflect off multiple layers and interact constructively or destructively
Iridescence results from thin-film optical interference, where the wavelength of light that reflects constructively shifts with viewing angle, changing the apparent color.
Question 6: When illuminating a red object with a green light source only, the object will appear:
- Bright red, as the surface pigment is unaffected by light color
- Nearly black, because the red pigment absorbs green wavelengths and reflects little light (Correct answer)
- Orange, due to additive mixing of red and green
- Magenta, as the complement of green
Correct answer: Nearly black, because the red pigment absorbs green wavelengths and reflects little light
A red pigment reflects red wavelengths and absorbs most others; under green-only illumination there is almost no red light to reflect, so the object appears very dark.
Question 7: The 'TLCI' (Television Lighting Consistency Index) extends CRI concepts specifically for:
- Theatrical stage lighting design
- Evaluating light quality as a camera sensor perceives it, not as the human eye does (Correct answer)
- Measuring daylight variation in broadcast studios
- Standardizing color temperature in outdoor film shoots
Correct answer: Evaluating light quality as a camera sensor perceives it, not as the human eye does
TLCI was developed because camera sensors have different spectral sensitivities than human eyes, so a high CRI source may still render colors poorly on video.
CCE Lighting & Material Interactions 3
A textile designer notices that a carpet sample looks greener on the showroom floor than in the client's home.
The most likely cause is: