IES Annual Conference Days 2+3 Trip Report

Cup of coffee with cream, the color is a light brown. In a cup labeled "Apollo 50th Anniversary." Sitting on the author's home desk. Keyboard and coffee pot visible in the background.
My wonderful cup of conference coffee

What a fantastic program. It’s been a long time since I have attended a real conference. Is attended the right word? After all I completed my IRB training today and went to my friends garage gym for bench press. I don’t think I would have done either of those things if I was traveling for the conference. But I did miss having coffee in the halls, elevator pitches of ideas, meeting new people and the many other important social functions of an in person conference. I suppose those are just a part of the times we live in.

Today was the third day of the conference but only my second day attending. In this post I’ll be just giving some highlights to ideas and sessions that I found particularly worth my attendance. A few quick general items: First, due to generous sponsorship I am able to attend for free as a student. I owe a great big thank you to the conference sponsors: Cree Lighting, Cooper Lighting Solutions, Acuity Brands, IES New York Section and Lumenwerx. Second, the conference is organized in such a way that no sessions over lap and all are conducted in a live webinar format. I especially enjoy the time that has been left for questions and the wonderful pacing between sessions by master of ceremonies, Shane Skwarek.

Day 2

For me, the conference started yesterday with two great sessions in the “Emerging Professionals” block. The first was given by presenters Dr. Tony Esposito and Dr. Kevin Houser. I’ve heard Dr. Houser speak before, by invitation to a manufacturer training event. I would highly recommend following his work which has been incredibly impactful in the lighting industry. His former student, Dr. Esposito, has been doing some very interesting work examining ways to work the various TM-30 metrics into workable recommendations for everyday lighting practitioners.

The two spoke about the Hunt Effect, a well known visual phenomenon in which colors appear less vivid, less saturated, when the illumination level decreases. On a cloudy-sunny day look outside at your window for a few minutes. You can see how the vividness of grass and bricks changes with the passing clouds. This is a very important effect for lighting designers to understand; Dr. Esposito and Dr. Houser explained that in dimly lit restaurants and museums the colors of our skin, our clothes, the food, decore, paintings, and artifacts all have much less vivid color than we would experience those same objects illuminated at working or outdoor lighting levels. Their talk “Lighting to counteract the Hunt Effect” gives a wonderful and concise solution: select fixtures which increase the saturation of objects. I.E. Those lighting fixtures and scenes which have a TM-30 Rg > 100 with a specific focus on the red hue bin #16.

It’s very interesting to me that red has emerged as such a critical color in these “Lighting preference” metrics that are used to justify the above work. Next, I’d expect blue to be the most significantly important and there is an interesting relationship between red and blue. Not that they make purple, but that they both exhibit the most extreme Helmholtz Kohlrausch factors for calculating visual brightness. It seems quite obvious that there is some relationship to hue and brightness, and brightness and colorfulness are closely related in the Hunt effect. I can’t be sure that the hue function from HKE is playing the same roll in making red an important color in lighting preference, but the idea is worth investigation.

My next favorite presentation was given by Naomi Miller from PNNL, and Steve Paolini from Telelumen. Steve is a man after my own heart, speaking everywhere about the wonderful beauty in high quality spectral reproduction from multi-primary fixtures. Having worked at ETC during my undergraduate program, 6,7,8,9+ primary lighting systems hold a special place in my heart. I first saw Steve speak about a year and a half ago at a very small conference on cutting edge video technology.

Naomi and Steve spoke about the variation that exists in natural lighting conditions, which, despite some extreme CCT or green and magenta appearance is still quite pleasant to enjoy on a park walk. In normal color fidelity measures we compare to the “ideal” spectrum of the same CCT. The presenters argue that this is perhaps too restrictive and idealistic. Instead we should take design notes from the natural world and all of it’s variation, variation in the spectrum and temporal intensity patterns of natural illumination. This might help bridge the gap between indoor and outdoor settings, but could it support other common design goals such as improving environmental satisfaction in an office or fatigue in an airport experience? Interesting ideas.

Day 3

Day three brought an onslaught of paper presentations. As an aspiring researcher, it was a particularly rewarding experience with some truly fantastic presentations. Thank you authors. I won’t bother writing on each paper that I enjoyed, but I would like to highlight two which stood out in my mind.

The first, a paper by Dr. Michael Royer explores the continued usage of the 1931 2˚ standard observer functions and wants for something better. Much significant and well agreed upon progress has been made with regard to color matching functions since 1931. However, huge numbers of standards and methods for calculating various things, such as CCT, ∆E2000, CIELAB, etc… are optimized for usage with 1931 CMFs. You might think that switching should be easy, however several decades of optimization for 1931 CMFs make even a small change to 1964 10˚ CMFs or newer standards causes an cause slightly misleading or slightly less optimal results. Stack a few calculations on top of one another and this small error has lead to some obvious visual mismatches or at least ambiguity in what should be considered the correct result. A significant amount of work lies ahead, and many many standards and formulas will need to be repoptimized but the effort will be worth while. That’s the idea anyway. It’s a problem that some feel should have been tackled many decades ago but none-the-less here we are.

My second favorite paper from today was offered by Dr. Dorukalp “Alp” Durmus and Dr. Royer, and covered one of my absolutely favorite topics. Working with multi-primary lighting systems (those with 4+ channels for which we can control the specific metamer that is used to reach a specific color) and quantifying their quality or capability. I’ve been toying around with the ideas for a special index of metamerism for multi primary lighting and it was wonderful to see a slightly different approach to some similar ideas. In Dr. Durmus’ paper the goal is to quantify the gamut or number of meaningful settings for a fixture, then we might be able to compare two fixtures and say this one has a larger capability.

The basis for the idea is to iterate over possible unique settings and count them, but in illumination the idea of two spectra being the same is not a simple problem. It’s more than a spectral problem, we are more sensitive to changes in some wavelengths over others. It’s more than a tristimulus problem, we know that two lights with the same chromaticity and intensity might not have the same color rendering properties and that is an important difference. So instead, much higher order dimensions must be used. Durmus proposes that “uniqueness” is some combination of Rf, Rg and TM-30 gamut shape. This sounds like a reasonable assumption, if two illuminants are similar enough on all three properties then there shouldn’t be any meaningful way, in terms of visual appearance, to tell them apart.

All in all, Dr. Durmus’ paper would get my vote for best paper of the day. I am looking forward to the publication of the proceedings.


All in all, I feel as exhausted and intellectually stimulated as I would at an in-person event. I’ve had no less than 4-5 new research ideas to distract me from my real work. Something very enjoyable but maybe at the displeasure of my advisor. All in all, well worth my time attending. I’m looking forward to the next several days of presentations.

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