Presented by the Designers Lighting Forum of New York

March 19–20, 2024
New York Hilton Midtown, New York City

2021 PANEL DISCUSSION: Metrics and Methods for Assessing Luminaire Uniformity

PANEL DISCUSSION: Metrics and Methods for Assessing Luminaire Uniformity

Belal Abboushi, Lia Irvin, and Eduardo Rodriguez-Feo Bermudez, Pacific Northwest National Laboratory

August 17, 2021

1:30pm – 3:00pm ET

1.5 LU Elective


Luminaire luminance uniformity is an important aspect that can affect visual comfort and lighting energy. Previous studies suggested that non-uniform luminaires with small high luminance sources were perceived glarier, compared to uniform luminaires. In this presentation, we will discuss the results of a recent study that examined perceived uniformity of different luminaire apertures in relation to commonly used and evolving metrics. Additionally, a method for measuring the uniformity of luminaire apertures has been developed and will be discussed. By effectively quantifying the uniformity of luminaire apertures, there is an opportunity to reduce discomfort from glare and improve luminaire energy efficacy.

Learning Objectives
1. Become familiar with the different metrics used to assess lighting uniformity.
2. Be able to discuss the effects of luminance distribution on uniformity ratings.
3. Identify design parameters that affect luminaire uniformity.
4. Discuss procedures used for measuring uniformity.


Belal Abboushi
Senior Associate Lighting Research Engineer, Pacific Northwest National Laboratory

Belal is involved in projects examining lighting uniformity, glare, daylight integration, and effects on occupant’s comfort and well-being. Belal earned a PhD in Architecture from the University of Oregon where he was involved in studies investigating daylight, visual comfort, and indoor environmental quality in buildings. He presented his research in various venues including IES Annual Conferences, LightFair 2019, and Greenbuild 2019. He is a member of the IES Discomfort Glare in Outdoor Nighttime Environments committee and the Daylighting committee.

Lia Irvin
Lighting Researcher, Pacific Northwest National Laboratory

Lia Irvin joined the Pacific Northwest National Laboratory (PNNL) as a post bachelors research associate in 2018, and works on the Advanced Lighting Science and Technology Research program. Her research interests include human factors in lighting, such as flicker and perception of luminance uniformity, which she investigates in both laboratory and field studies. Lia earned a Bachelors of Science with Honors in physics from the University of St Andrews. During her studies, she completed a dissertation project working with nanofabrication and encapsulation to develop more efficient microdisk lasers for bio-applications.

Eduardo Rodriguez-Feo Bermudez
Systems Engineer, Pacific Northwest National Laboratory

Eduardo Rodriguez-Feo Bermudez is a Research Associate at Pacific Northwest National Laboratory, in the Lighting Science Research group. This includes contributing on the assembly of the Obscuration Apparatus and helping each of the individual components communicate with each other through a Python based GUI.