This course discusses color science and various lighting technologies, with a focus on LEDs. It covers topics like the nature of light, color perception, color measurement, and how different light sources render colors. The presentation explores challenges in quantifying color quality and discusses how LEDs can meet and exceed expectations for color rendering compared to other light sources. It provides examples of how high-quality color rendering from LEDs can benefit applications and industries.

2. Presenter: Eric Haugaard, Cree LED Lighting

3. Credit(s) earned on completion of this course will be
reported to AIA CES for AIA members. Certificates of
Completion for both AIA members and non-AIA
members are available upon request.
This course is registered with AIA CES for
continuing professional education. As such, it does
not include content that may be deemed or
construed to be an approval or endorsement by the
AIA of any material of construction or any method or
manner of
handling, using, distributing, or dealing in any
material or product.
___________________________________________
Questions related to specific materials, methods, and services will
be addressed at the conclusion of this presentation.

4. Through the ongoing advancements of LED technology, the
possibility to provide improved color quality performance and
value to the application space has never been greater. This
presentation will address the aspects of color science and the
various light source technologies used for general illumination,
with a strong focus on Light Emitting Diodes (LEDs). Included
will be a review of the most widely adopted methods and
metrics for describing all aspects of color quality and
performance for general illumination solutions. Examples
illustrating the current and future possibilities for accurately
predicting color quality performance and value in the general
illumination space will be discussed.

5. 1. Exploring Light in Nature vs Man Made Light.
2. Light Source Science – LED and Traditional Technologies, A look
into the Future With LED
3. Understanding Object Color and the Importance of Broad Spectrum
Sources.
4. Challenges in Quantifying Color Quality
5. Meeting Color Quality Expectations in the Application Space

6. Light – What is it made of?
Light is made of waves
(technically: electromagnetic waves of radiant energy)
very small waves…
Lights wavelength is measured in
billionths of a meter, nanometer (nm)
UV, Infrared (IR) heat, cell phone radio
waves, X-rays are the same waves…
just longer or shorter
Visible Light is wavelengths between
380nm and 780nm

7. • Different Wavelengths = Different Colors
Light comes in different colors, spread across the rainbow of hues we
call the visible spectrum.
Red waves are the longest, purple the shortest

8. 8
Blue Green Red
Visible Light

9. How Do Humans “See” Color?
• The eye contains cones and rods - cones are color sensitive and used for
high light level vision (photopic) , rods are for night vision (scotopic)
• Three types of cones – long, medium and short .. Sensitive to red, green
and blue areas of the visual spectrum
• Cones are concentrated in high density in fovea, Rods are spread across a
much larger area inside the eye

10. Sunlight
Twilight
Starlight

11. Color Intensity Perception
White light consists of many colors
mixed together
Natural White Light (such as
sunlight) consists of a continuous
spectrum of all colors
Wavelength
Power
Relative Human
Eye Sensitivity

12. The Human Eye Response Curve
555 nm Peak

13. 13
1931 CIE Chromaticity Diagram
1976 CIE Chromaticity Diagram
How It Works
• Monochromatic (“high Saturation”) colors are on the
outside edge of the diagram
“The Spectral Locus”
• All combinations of colors are on the inside, with white
colors in the middle

14. 14
1931 CIE Chromaticity Diagram
Red
Green
Blue

16. 16

17. Steel @ 1500K
Warm White
B type star >11,000K
Cool White
Noon time sun @ ~ 6000K
Cool White
Blackbody Radiation
Tungsten @ 2700K
Warm White
1931 CIE Chromaticity Diagram

18. Color Gamut

19. 19
Blue + Yellow Phosphor
Blue
Peak
Yellow
Phosphor

20. CIE 1931 Color Space

21. CIE 1931 Color Space

22. White Light for General Illumination
Creating White Light
WHITE
LIGHT

23. LIGHT EMITTING DIODE
Epitaxial Layer
Substrate

24. LIGHT EMITTING DIODE

25. LED Package

26. Blue + PhosphorGenerating White Light with LEDs
Phosphor
Blue LED

27. Spectral Power Distribution
Daylight Incandescent
Phosphor Converted LEDs

28. Spectral Power Distribution
Phosphor Converted LEDs
Metal Halide Fluorescent

29. Phosphor Converted LEDs

30. Precise Color Tuning

31. 31Precise Color Tuning

32. 32
• Even with the two source method choices abound
• Here is a system that starts and ends on the BBC
6500K
2700K
2700
Tc(K)
6500
Two Source White Color Tuning
Credit: Finelite, Inc.

33. 33
• Here is a system that starts above the Black Body Curve and ends
below it
6500K
2700K
2700
Tc(K)
6500
Two Source White Color Tuning
Credit: Finelite, Inc.

34. 34
• Customer acceptance will determine which two source White Color
Systems provides the best value
6500K
2700K
2700
Tc(K)
6500
Two Source White Color Tuning
Credit: Finelite, Inc.

35. Comparing Spectral Power Distribution
Incan-
descent
Daylight
3000 K 3000 K

36. Color Rendering

37. Color Rendering Index (CRI)
– A quantitative measure of the ability of a light source to reproduce
the colors of various objects faithfully in comparison with an ideal
or natural light source
– Ranges from 0 (poor) to 100 (excellent)

38. Object Color

39. Spectrum
Object Color
Vision
Object Color

40. Color Rendering Index
Daylight
In general terms, CRI (Ra) is a measure of a light source's ability to show
object colors "realistically" or "naturally" compared to a familiar reference
source, either incandescent light or daylight.
None of the 8 test colors used to calculate CRI are saturated. So, CRI is a
poor measure for indicating how well a light source illuminates saturated
colors.
Even with a high CRI (Ra), color rendering of saturated colors can be poor.

41. CRI With Expanded Ra
Example

42. Color Rendering Index – R9
U.S. Department of Energy (DOE) Comments:
0 1007550
Poor Good Very good Excellent

43. Color Like Nature Meant it to Be!

45. This produce may appear
reasonable under a broader
color spectrum source.
Why is full spectrum color important?
What would you expect to happen
under a Low Pressure Sodium lamp?
Color Contrast

46. LPS LED
Color Contrast

47. What’s the Value of
Exceptional Color Quality?

48. 52Good CRI and Red Color Rendition is Important
For Illustrative Purposes Only
Images: Courtesy GE Lighting

49. 53
For Illustrative Purposes Only
Good CRI and Red Color Rendition is Important

50. Different Colors…
Should Look Different
Help People
Look Their Best

51. Tunable Fitting Room Lighting
Photo Credit; Lux Magazine

52. Published in March 2015
Collaborative paper between CLTC, University of British Columbia and the National Research Council of Canada.
High Color Rendering Can Enable Better Vision
without Requiring More Power

54. Dim-to-Warm Solutions
EXAMPLE:
• Follows above curve from 2700K to 1800K
• At 1800K, similar color to candle light,
sunset, and sunrise
• High CRI throughout dimming
• Color changes naturally just as an incandescent lamp

55. Seeing is Believing…

56. Seeing is Believing…

57. LED Metal Halide
830W 3,070W

58. Daylight at Night?

59. Metal Halide
4000K ~65 CRI
R9 <0
LED
5000K 90+ CRI
R9 50+

60. 64
400W Metal Halide

61. 65
LED Solution

62. 67“Lighting Class” LED Devices

63. 68Color Stability
Blue Shift
Green Shift Yellow Shift

64. 69Long Term Color Point Stability
This is poor color consistency…
Typical Fluorescent and Metal Halide Challenges
Greater Possibilities With LED Solutions

65. 70

66. 71
New Color Rendering Metrics
are Being Explored
(IESNA TM-30-15)

67. 72
Credit: Royer, US DOE

68. 73
Credit: Royer, US DOE

69. 74
Credit: Royer, US DOE

70. 75
Credit: Royer, US DOE

71. Presenter: Eric Haugaard, Cree LED Lighting

72. This concludes The American Institute of Architects
Continuing Education Systems Course