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Color Metrics: 50 Shades of White

  • SmithGroupJJR (cafe) 1700 New York Avenue Northeast #100 Washington, DC, 20002 United States (map)

Chromaticity and the Color of White – Perception vs. Scientific Testing

By now we’ve all experienced, or at least seen, the color consistency problems with LEDs and other white source types (fluorescent lights and metal halide are also culprits). A row of downlights may appear as a random pattern of pink and green dots!

Tightness of binning, MacAdam Ellipse, and SDCM are commonly discussed and are showing up on more spec sheets. But are these the right metrics? And how tight is tight—and relative to what? Where are these numbers coming from? How do you know if your spec is being met? What is the difference between duv and du’v’ and why do we have 3 different chromaticity color spaces to contend with?

The program will begin with a quick refresh on the key principles of color perception—spectral power distribution, gamut area, tristimulus values, CRI, R1-15, and CIE 1931, 1960 and 1976 chromaticity charts.

In the second part of the program, we will physically test and evaluate what these metrics and measurements actually mean in terms of perception. You might have read the studies (which will be discussed), but what about your own perceptions?

The measured color will be plotted live on the Chromaticity chart. Attendees are encouraged to bring their own light source for testing.

Light sources for testing must be:
1. a complete luminaire (source + socket + (necessary driver/power supply) + cord and plug—for 120V); and
2. must fit in a 12” cube.


Star Davis, associate IALD, is a Lighting Consultant at Arup in New York, where her current projects include the San Francisco Museum of Modern Art Expansion and the Lowline. Davis is an adjunct professor of lighting and daylighting at Parsons, The New School for Design, and currently teaches the Lighting Systems Technology seminar and the Allied Studio, a multidisciplinary design studio with Lighting Design, Architecture, and Interior Design graduate students. She earned a Master of Fine Arts in Architectural Lighting from Parsons, and a Bachelor of Science in Engineering from Duke University.


$15 (IES members) / $30 (non-IES members) / $15 (EP or students, non-IES) / FREE (IES EP)

RSVP: by January 22


Earlier Event: December 8
MCLA Project Tour