I recently had the pleasure of interviewing Andrew Kites, Global Product Manager, Philips Lighting. The topic: light and color. I’m happy to share his responses with you here. The interview informed an article I wrote for the November 2017 issue of tED Magazine.
DiLouie: How do LEDs differ from traditional light sources in terms of color characteristics, and what opportunities does this create?
Kites: Traditional light sources are generally broad spectrum emitters that produce high quality color rendering of objects. Color LED sources emit light in a narrow spectral band, and phosphor converted white LEDs provide a narrow peak in the deep blue wavelength range, while also producing high irradiance in the 470 to 630nm spectral range.
LEDs allow us to isolate and understand the impact of specific spectral bands on human physiology, plant growth, environmental impacts of electric light, etc.
DiLouie: With LED technology, it is possible to precisely engineer the spectral power distribution of a product. What possibilities and markets does this serve/create?
Kites: It is possible, but not necessarily practical. LED sources have seen dramatic cost reduction, much of this driven by manufacturers reaching economies of scale and R&D breakthroughs. The industry has converged on a somewhat limited set of phosphors and pump emitters to help drive cost down and push efficacy up. Using multiple narrow band emitters (red, blue, green, amber, etc) and optically mixing these colors to produce white light is one way lighting companies can test new concepts in applications where white LED light sources aren’t sufficient. We can now produce high quality white, and color in the same light fixture. Retail, healthcare, horticulture, and general architectural applications will benefit from this tech.
DiLouie: In 2015, the IES introduced the TM-30 method of evaluating color quality. Do you see designers and manufacturers getting behind TM-30? For what application is the precision of TM-30 ideally suited? What do you think will happen next in terms of new color standards?
Kites: At this time, we have not seen large adoption of the TM-30 standard. As the industry better understands how use the color information that TM-30 provides, we could see adoption pick up. As lighting designers see how color fidelity and gamut can help them deliver application specific color metrics, TM-30 data will become important. Ease of use is also an important factor.
DiLouie: Please describe the process of binning and how standards and manufacturer methods ensure good color consistency. Is there anything new to report in this area in terms of new standards or technology?
Kites: Color consistency from credible LED manufacturers has improved significantly since white LEDs were first produced. Some manufacturers have gotten much more skilled at producing LEDs that are closer to the center of the ANSI bin for that CCT, reducing waste in manufacturing from out of spec product, reducing LED costs, all while improving color consistency. There are no new standards or technologies for white light binning widely available.
DiLouie: The California Title 20 standards require a bump in general-service lamp CRI that may result in 90+ CRI being standard but with the tradeoff being higher cost and potentially lower energy savings. What is your view of these regulations, and (if applicable) how is your company responding?
Kites: As the industry has concluded, CRI is not necessarily the best metric to measure color quality of LED sources. Instituting regulation without properly weighing cost/benefit could hinder the adoption of LED lighting and/or impede innovation.
Many of our customers feel that the existing LED light quality standards are “good enough” for general purpose applications. CRI was developed on the basis of a reference lamp and helped compare quality of light across different lamp types. Over time, as this became an important metric to specifiers, manufacturers started to focus on setting minimums for certain applications. However, the ability of a human eye to differentiate between a CRI of 88 and a CRI of 90 is very low, since it’s a mathematical metric, and not based on human perception differences of color fidelity.
DiLouie: How important is color to circadian lighting, and where does the industry stand on understanding the science and developing products and a market for it?
Kites: The fundamental research in light and well-being is more than twenty years old. Our approach is to test and adapt systems, which can be reconfigured Research is ongoing to determine the appropriate light levels, spectral content, and lighting design that provides support for human circadian biorhythms. The research points to humans generally having a biological response to both blue and red wavelengths. easilyThe research into lighting and its effects is ongoing and we continue to uncover new insights.
DiLouie: Are there any other important new developments in lighting and color?
Kites: Using color for design, functional, and physiological impact will continue to grow as control systems become more color friendly. The psychological impact that colors can have on people, and the associations that people have for various colors and elicit emotional responses. As research develops, we will see how these emotional and psychological impacts color has on humans, plays out in various applications and use cases.
DiLouie: Why is color important to understand for electrical distributors selling lighting?
Kites: Color is important in order to acheive the desired lighting effect. Customers new to LED lighting will look for recommendations and distributors have the opportunity to help educate the market.
DiLouie: How can electrical distributors turn their understanding about color into lighting recommendations and sales?
Kites: Matching customers speed with the correct products will help speed LED light source adoption. For multi-color light fixtures, knowledge of controls and general installation requirements will ensure customers get the most out of their digital lighting systems.
DiLouie: How should electrical distributors qualify products based on color performance? What performance features, metrics and standards should they be paying attention to?
Kites: CCT and CRI at a minimum and CRI R9 values are becoming increasingly important. For tunable lighting systems, color mixing, optical beam quality, CCT range, how well it tracks the black body curve, color consistency across luminaires, and TM-30 values are also important.
DiLouie: If you could tell the entire electrical industry just one thing about lighting and color, what would it be?
Kites: Lighting has a profound effect on the human body, how we feel, and how we function. Whether it is student focus in the classroom, employee comfort in the office, shopper behavior inside the store, or patient recovery in the hospital, it is quite easy and exceedingly beneficial to customize an indoor space using the right light, with the right spectral content, at the right time in order to support a diverse range of daily activities.
DiLouie: Is there anything else you’d like to add about this topic?
Kites: Spectral knowledge and color-tunable systems are new and exciting to the lighting industry, and will bring more challenges and opportunities to the market. The more we know and understand how these systems can positively impact our customers, the bigger the opportunity to bring value to our customers.