On February 24th I’m giving an online presentation called Designers Thinking About Light to the Vancouver section of the IES. I’ll be talking about how lighting designers think about light as an artistic medium. The presentation will include some ideas you probably know, as well as some approaches that will be new. To register, visit the IES Vancouver Section web site.
I tell my students that we’re lighting designers not scientists, but that it’s good to understand some of the science that underpins our work. This is especially true when the science is out of date and produces results that don’t necessarily agree with our vision and/or perception. It’s frustrating and amazing to me that as individuals we’d never agree to use a broadcast only TV and give up our modern cable and internet channels. We’d never agree to use a flip phone and miss out on all of the upgrades and improvements that have been developed over the years. Yet as an industry we seem perfectly happy to continue to use 75+ year old technology with known flaws when we calculate color rendering, measure brightness, plot chromaticity in color spaces, etc. Our industry doesn’t seem interested in “upgrading” to get the latest features like less metameric mismatch and measurements that better align with our vision and perception. But, I continue to shout into the void about these things.
One of these topics is the standard observer. This article, online and in the current issue of LD+A, looks at the problems that can arise from continuing to rely on the 1931 standard observer, and not “upgrading” to the 1964 or 2015 standard observers.
In September at ArchLIGHT Summit, Tony Esposito and I gave a series of demonstrations on the spectral flexibility of LEDs and the possibilities they present with regard to color rendering. While there we spoke to Sam Koerbel on his LytePod podcast about the basics of the new measures introduced in Annex E, and discuss why TM-30’s multi-dimensional approach to quantifying color preference is superior to the old-standby in the industry: CRI. Our discussion is now available. Give it a listen.
I’m excited to announce that the second edition of my book Designing with Light: The Art, Science, and Practice of Architectural Lighting Design is now available as both a soft back and ebook. It can be purchased from Amazon, Barnes & Noble, Wiley, and many other retailers, and makes a terrific gift this holiday season. Order yours today!
Last week Tony Esposito and I presented seminars at ArchLIGHT Summit in Dallas, TX. The topic was TM-30 and the deep information that it provides us about a light source’s spectrum and the resulting color rendering. CRI, of course, only evaluates fidelity – how close a light source matches its reference light source. But CRI penalizes all deviations and says nothing about the rendering of individual colors. Nor does it help us understand if the deviations from the reference are acceptable to viewers.
A small part of our demo is shown below. It illustrates how two light sources can have the same fidelity (in this case Rf of 70) but wildly different spectra that produce wildly different color rendering results. This is the great strength of TM-30, a deeper insight into the effect of a light source on illuminated objects and their color appearance – not just fidelity, but chroma shift, hue shift, and the perceptual implications of those shifts.
The video below shows the color appearance shifts. The graphic illustrates that even though the Rf is 70, the first light source renders objects in a preferred manner (Preference Priority Level of 3 or P3) and increases vividness (Vividness Priority Level of 2 or V2). At the same Rf the second source mutes colors and fails to achieve any of the Design Intents and Priority Levels specified in TM-30’s Annex E.
A reminder that Tony Esposito and I will be presenting Specifying Light Source Color Rendition three times at ArchLIGHT Summit in Dallas next Tuesday and Wednesday, the 21st and 22nd. Hope to see you there!
My colleague Tony Esposito and I will be giving a new TM-30 seminar and demonstration at ArchLIGHT Summit 2021 in Dallas on September 21st and 22nd. We’re working on a new, and we hope more attendee friendly, presentation and an all new set of demonstrations to explain TM-30s Annex E specifications. The demo will include, for the first time, live models of different ethnicities so attendees can evaluate the impact of of the specifications on skin tone. I hope to see you there!
Many of us on the IES Color Committee, myself included, have written and spoken about TM-30 and how to use it. I’ve written posts on this blog (click on the color rendering tag to see them all), authored articles, spoken at IES Annual Conferences, given webinars to architects and lighting designers, and assisted manufacturers in adding TM-30 data to their cut sheets. Despite our efforts, and those of others, TM-30 is still not as well understood and broadly implemented as it could be.
A recent issue of Leukos featured an excellent tutorial by Michael Royer of Pacific Northwest National Laboratory. In it, he describes the development of TM-30, color rendering fundamentals, the workings of the TM-30 calculation framework, TM-30 measures and their meaning, and more. That article is now available on the US Department of Energy’s website here. Anyone who’s unsure about TM-30 will find it immensely useful.
On a related note, many members of the IES Color Committee, myself included, can make themselves available to answer questions or present webinars to architects, interior designers, lighting designers, electrical engineers, sales reps, and manufacturers. If you’re interested, use the Contact Jason Livingston link above to send me a message. If I’m not available or the right person for your organization I’ll find someone who is.
Recently, a well-known lighting designer gave a presentation at a well-known lighting conference. During the Q&A he was asked his opinion of TM-30 and replied that it was too hard so he just specified CRI>90. At the risk of sounding like a jerk I have to say that maybe it was too hard for him, but it’s not too hard for most of us. Here is a brief list of new things lighting designers have had to learn over the years.
The introduction and transition to electronic ballasts and transformers meant that we had to learn about reverse phase dimming and control protocols.
The T5 lamp meant we had to change our layout patterns to accommodate lamps that weren’t standard 2’, 4’, and 8’ lengths.
Metal Halide lamps, especially PARs, meant that in exchange for energy savings we had to learn about the color rendering of a new type of lamp, and give up dimming.
Daylight harvesting and daylight responsive designs meant we had to learn about daylight zones, photosensors, and daylight harvesting control systems.
White LEDs meant we had to learn about another light source and its specific pros and cons, including different color rendering properties due to its SPD.
Circadian lighting means we are all in the process of learning how and when to apply the most current scientific evidence to certain project types. Since the science is constantly advancing on this topic, we must be aware and continue to educate ourselves.
Regularly updated energy conservation codes mean that as we begin to memorize the lower LPDs and changes to control and daylighting requirements, we have to relearn that information because it changes every three years.
Most recently, we’re supposed to enthusiastically embrace IoT, adding new hardware and controls to our lighting control systems.
There is a ton of TM-30 educational material available, including posts on this blog here, here, here, here, here, and here. There’s this article on the IES’s FIRES Forum, and this page on the Department of Energy web site. Manufacturers are also providing education including DMF Lighting, Soraa, Premier Lighting, Alphabet, and Lighting Services Inc. Then there are the articles in trade magazines and sites such as Lux Review and Architect Magazine, not to mention many articles in Lighting Design and Application and Leukos (no links because they’re behind the IES login). In addition, there have been presentations at other conferences (some given by me) at the IES Annual Conference, LightFair, and LEDucation.
If that’s not enough for you, let me know. I have a presentation approved for one AIA HSW LU, so if you’re architectural firm wants to learn more let’s set up a presentation. Ditto for lighting design firms and teachers of lighting. If I’m not available there are a half dozen others on the IES Color Committee who regularly give TM-30 presentations. You can learn TM-30. I’m here to help.