MICHAEL SIMINOVITCH, KONSTANTINOS PAPAMICHAEL, and LORNE WHITEHEAD argue that California's Title 20 rulemaking that essentially mandates 90-CRI LED-based lamps is a forward-thinking policy driven by the evolution of SSL technology and the realities of the human visual system.
The California Energy Commission (CEC) has established regulations in the Title 20 rulemaking for consumer LED lamps that would connect advances in lamp luminous efficacy with other important performance aspects, such as excellent color quality. This new approach to solid-state lighting (SSL) is founded on the premise that next-generation LED lamp technology can and should provide an optimal combination of key performance attributes, including luminous efficacy, color rendering, and longevity. The resulting LED lamps will facilitate the long-term transformation of the residential consumer marketplace from incandescent lamps, while retaining the excellent color rendering that consumers have always enjoyed.
Among many aspects of the CEC policy, the essential requirement that LED lamps have a color rendering index (CRI) of 90 has proved controversial to some in the lighting industry. Indeed, some participants in the regulatory process have stated that the CEC should not consider product quality, claiming that a combination of consumer preference and competition among suppliers will ensure consumers' access to products with an optimal blend of quality, energy savings, and affordability. But that mechanism only works for quality factors that are readily apparent to the customer at the time of purchase. In contrast, for quality factors that are not apparent at the time of purchase (such as color rendering), lack of regulation and competition can produce what is sometimes called a "race to the bottom" in terms of product quality. Equally problematic is narrow regulation that incentivizes efficacy in lighting (lumens per watt or lm/W), creating an incentive to lower color quality for compliance. These issues have prompted the call to action for consumer-oriented regulations that support the best combination of quality factors in this rapidly evolving marketplace.
There is an important relationship between lamp efficacy and color fidelity. Opponents of the CEC regulation claim that high-color-fidelity lamps consume more energy than the lamps they replace. That is a mischaracterization, partially fueled by a common misunderstanding. Many incorrectly think that the human eye's simple luminous efficiency function, which assesses lumens, tells us most of what we need to know about general-purpose lighting. In truth, more sophisticated color response functions are needed to assess the value of light for perceiving and differentiating colors. People are quite insensitive to the quantity of lumens but very sensitive to color rendering changes.
It is certainly true that a lamp can be made to produce slightly more lumens by sacrificing color quality, but those few extra lumens of poor light are simply not needed or even noticed - and the net result is not better lighting. An intelligent combination of quality metrics is essential for optimizing lamp design. Put simply, high-color-quality lamps can use the same amount of power as lower-color-quality lamps, and the net result is much better color quality without a perceptible reduction in illuminance for the same energy.
Spectral power distributions are compared for a typical 80-CRI LED light source, a 90-CRI LED light source, and a 100-CRI incandescent light source. (Illustration courtesy of California Lighting Technology Center.)
Some find this idea perplexing because they do not understand that the lumen itself is simply a very incomplete measure. When manufacturers aim to produce more lumens for the same amount of electricity they must artificially concentrate radiant power, to some degree, in the central portion of the visible spectrum.
This reality is in contrast to incandescent lamps and daylight, which have very high color-rendering-index values, with radiant power spreading more broadly throughout the full visible spectrum. Incandescent lamps and daylight enable accurate color perception of the many bright and subtly colored materials found throughout most homes.
At first glance, higher efficacy alone may seem most important to utilities and energy-efficiency advocates, but as a single figure of merit it doesn't address the ability of a light source to faithfully render colors in the home. In other words, low-color-quality light does not efficiently meet the needs of human vision.
To put that another way, consumers don't purchase lumens for their homes - they purchase visual service. Visual service is determined by the breadth of the human visual system, the wide variety of colored surfaces in our homes, and the spectral power distribution of the light being supplied. The lighting industry to some degree agrees with this concept, and generally sets a floor of color rendering of 80 for general-purpose lighting. However, no one has ever demonstrated and documented that light sources with a CRI of 80 are equal to incandescent in terms of overall lighting experience, or color quality.
In this case, the burden of proof clearly falls on those claiming "CRI 80 is good enough." They would need to show that people cannot see the color rendering errors produced by such products, or, alternatively, that the visible color distortion is judged by consumers as an appropriate way to produce the invisibly small resultant gain in raw lumens. They do not show proof, for a simple reason - it is simply not true.
The "good enough" advocates repeatedly say that since people are buying 80-CRI lamps today, the lighting quality must be fine. At the same time, some mainstream manufacturers, while objecting vigorously to the proposed California standards, are aggressively marketing high-efficacy, high-color-rendering phosphors. Furthermore, most mainstream manufacturers offer products with CRI above 90. The current misadventure into poor-color-fidelity light sources, whereby inferior LEDs are being purchased, is merely an indicator of both human adaptability and a poorly informed marketplace that doesn't really understand or fully appreciate the choices or the possibilities.
Informed consumers would not purposely choose a poor-color-fidelity service experience. Our society's collective, maintained use of a broad-spectrum incandescent light source, in juxtaposition to readily available, affordable, high-efficiency compact fluorescent lamps (CFLs), indicates that consumers do like high-color-fidelity light sources as well as the other quality benefits associated with incandescent lamps such as smooth dimming and controls interoperability.
Today, typical LED lamp designs that meet the Energy Star requirements for an 80-CRI rating have depleted energy in the long-wavelength red end of the visible spectrum, yet these long wavelengths are highly appreciated by consumers. In fact, much of our color experience relies on the ability to make fine color discriminations between subtly different hues, often arising from slight shifts in long-wavelength content.
Our day-to-day surroundings are often biased toward those longer red wavelengths, including flesh tones, foods, woods, fabrics, and other important surface materials encountered in the home. The importance of high color quality is broadly recognized by professional lighting designers who are informed consumers, as one will rarely find "good enough" 80-CRI rated lamps in the illumination of high-end retail, meat or fish displays at the market, fruit and vegetable displays, art galleries and museums, fine dining restaurants, medical facilities, art studios, and other applications that rely on an accurate, high-fidelity color experience.
Mainstream industry understands this reality and is already aggressively marketing high-color-quality products into these markets. Why do some in the industry think that the lighting of the American home would be any different or less worthy in terms of color appreciation? This is neither an energy-efficiency, nor an affordability issue, as some have falsely claimed.
The essential difference is that the homeowner market place is largely uninformed, and sadly misinformed, when it comes to color quality. Product labeling attempts, such as LED Lighting Facts, have historically provided both limited and misleading information to consumers, making it difficult for them to make informed choices. Ordinary American consumers don't have the benefit of a lighting designer, architect, or lighting color expert.
Understandably, consumers have difficulty navigating the variety of products in retail outlets, and they are often influenced mainly by price or brand recognition. In the absence of trusted, clear information on the importance of color, they may understandably make purchase decisions that are not in their best interest. Overall, this places a responsibility on the lighting industry to do better.
In the past, the industry has often spoken of the importance of educating consumers about good lighting. It is now time to help educate the public on the value of both high efficiency and high color quality so that they can enjoy the lighting in their homes. Instead of opposing forward-thinking regulations such as those proposed by the CEC, the industry should be proactive and begin informing the American public about the value of products that render all colors with a high degree of fidelity, fulfilling the full promise of next-generation LED light sources.
The American consumer should be able to enjoy the same level of color experience with LED lamps that they currently enjoy with incandescent lamps - without having to consult with a lighting professional. Some in the industry argue that doing so will increase cost, but this is based on outdated information. Product innovators have already responded to the California marketplace, and we are already seeing high-CRI lamp configurations with retail pricing less than $8 per lamp. Data have already been compiled and presented to the CEC demonstrating that the cost differential between high-color-quality products and products that meet the minimum Energy Star requirements is small, diminishing, and will largely disappear with time and volume.
American lamp manufacturers have already introduced 60W-equivalent LED lamps with high color quality and efficacy. In fact, one of the largest lamp manufacturers in the international marketplace produces a high-color-quality lamp that is more efficient than the majority of the Energy Star products evaluated at the California Lighting Technology Center as part of ongoing market assessments. These commercially available lamps are in stark contrast to the aforementioned industry objections. The performance and cost attributes for these and other lamps are of public record.
It's time that the American consumer has broad access to practical LED lamps with high color fidelity.
LEDs Magazine comments on CEC Title 20
We at LEDs Magazine have covered the CEC Title 20 regulations extensively starting with an online article on the formal endorsement of the rulemaking back in February: "California tightens color performance of LED-based lamps".
Moreover, we published an editorial on the topic in our March issue ("California missteps with Title 20 LED lamp regulations"). And we continue to believe that the CEC regulations are inappropriate despite the arguments put forth by the authors of this article.
Furthermore, the CEC action may prove irrelevant for most general-service LED lamps sold even in the state of California. As we wrote in April, federal regulations being developed by the US Department of Energy (DOE) will likely trump the CEC regulations ("DOE rulemaking could dash California Title 20 sting"); more information on that topic could be available shortly after this article is published. Watch our website for updates. - Maury Wright
MICHAEL SIMINOVITCH and KONSTANTINOS PAPAMICHAEL are professors at the University of California, Davis and leaders of the California Lighting Technology Center (cltc.ucdavis.edu). LORNE WHITEHEAD is a professor at the University of British Columbia (https://www.ubc.ca/).