CRI Inches Forward

The CIE’s Color Rendition Index (CRI) has long had several known weaknesses including outdated components of the calculations, a limited set of color samples, and standard reporting of only one piece of data (the average color distortion of the first eight colors, known as the General Color Rendering Index or Ra). After more than a decade of stalemate it seems that the IES’s TM-30 has convinced the CIE to make another attempt at updating CRI.

In a recently released position statement the CIE announced that the CRI technical committee (TC 1-90) has taken up the problem again and is expected to write a technical report on a new, improved color fidelity metric that can update CRI before the end of 2016. They will use TM-30 Rf as the basis for their work. Another committee, TC 1-91, will write a report on a color preference metric in the same time period.

This is both good and bad news. CRI is the international standard for measuring and reporting light source color rendering. It is long overdue for an update, and I’m glad to see the CIE working on it. On the downside, the press release makes it sound as though 1) parts of TM-30’s Rf may be incorporated, but the CRI fidelity metric will be a new creation 2) we may see the addition of a color preference metric but TM-30’s gamut metric Rg apparently isn’t being considered. The biggest reason that this is a concern is the amount of time it takes to create the work, gain internal consensus, approve the work, and gain organization approval – all of this before the work can be released to the larger lighting community for consideration. I think it is extremely optimistic to think that the two committees can write meaningful reports on these issues in only one year, especially given the difficulty they’ve had reaching consensus in the past.

I would much rather see the CIE committees study TM-30 and report on its strengths and weaknesses before deciding that it won’t work and they should start over. Adopting or modifying TM-30 can happen much quicker than developing one or more new metrics. TM-30 took three years to develop and the industry shouldn’t have to wait another three years for an updated metric that has the CIE’s approval.

This Is Not About Light

A Public Policy Polling (PPP) survey earlier this month revealed that an astonishing 32% of respondents supported making Christianity the official religion of the U.S., and that 14% were not sure. The political breakdown was as one might expect, with 42% of conservatives in favor, but 28% of moderates and 25% of liberals also in favor – of re-writing the First Amendment to the Constitution! This is not a blog about religion or politics, but I have to say something about the rising sentiment that the U.S. is, or was intended to be, a Christian country, or that it was founded on Biblical principles. Saying that the U.S. should have an official religion flies in the face of the First Amendment. It is both un-Constitutional and un-American.

Let me start by defining a few terms. A democracy is a form of government in which the supreme power is vested in the people and exercised directly by them or by their elected agents under a free electoral system.. A republic a state in which the supreme power rests in the body of citizens entitled to vote and is exercised by representatives chosen directly or indirectly by them.. A theocracy a form of government in which God or a deity is recognized as the supreme civil ruler, the God’s or deity’s laws being interpreted by the ecclesiastical authorities. So the U.S. is a democratic republic, with some issues decided by a popular vote and some issues decided by our elected representatives. Religious leaders do not decide issues because we are not a theocracy.

But, were we intended to be guided by religion? Was the government organized around biblical principals, as so many conservatives claim and desire? The surest way to answer that question would be to ask the founding fathers. Alas, they’ve all been dead for two centuries now but we don’t have to live in uncertainty. There are literally hundreds of thousands of pages of public and private documents that clearly detail their thoughts, desires, and intentions as they declared independence from Britain and created our curent form of government. We can end the bickering by simply looking at what they wrote. Now, I make no claims to being an historian, but I have long had a strong interest in U.S. history. I can say for certain that among the founding fathers Adams, Franklin, Hamilton, Jefferson, Madison, and Washington had no such plans for our country.

Did the founding fathers believe in God? In their own way, yes. Most of them were members of various Protestant sects. Benjamin Franklin was well known as a Quaker. Many were Deists, believing that while God created the world he does not interfere in it. But that doesn’t mean that they wanted a government based on religion. Let’s remember that one of the most significant reasons people emigrated to the colonies was to escape the state sanctioned religions of the European countries to be free to worship as their conscience dictated. This was still true in the late 1700’s, as the founders unquestionably knew. Establishing a state sanctioned religion under the new government was anathema to their experience.

The Declaration of Independence explains to the world why the colonies intended to separate themselves from Britain. The first two paragraphs provide a general explanation that is followed by a list of 27 items demonstrating the failure of the King to respect and protect the rights of the colonists. This is followed by two closing paragraphs. I think there are two important items here. The first is that there are mentions of, and appeals to, the “Laws of Nature and Nature’s God” “Creator” “Supreme Judge” and “Divine Providence” but no explicit mention of the Christian God. More importantly, none of the itemized complaints mentions God or the King’s failure to establish, implement, or enforce Biblical precepts. The colonies separated from Britain for secular, not religious, reasons.

The U.S. Constitution makes absolutely no mention of any god or higher power. The first ten amendments to the Constitution, the Bill Of Rights, were being circulated and advocated even before the Constitution was passed. In the First Amendment we find the only mention of religion, and that mention is part of a prohibition, “Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof…” which is known as the Establishment Clause.

The Federalist Papers were written by Alexander Hamilton (first Secretary of the Treasury), James Madison (fourth President of the United States), and John Jay (first Chief Justice of the Supreme Court) to convince the citizens of New York to vote in favor of the Constitution. They are one of the most cited documents in decisions issued by the Supreme Court. Not one of the 85 papers published between 1787 and 1788 discusses for the role of religion in the new government. In fact, they are silent on the subject because it simply wasn’t a consideration by those who drafted the Constitution or by those voting on it. The Anti-Federalist Papers are silent on religion for the same reason.

The Virginia Statue for Religious Freedom, written by Thomas Jefferson and passed by the Virginia General Assembly in 1786, clearly states that no one shall be compelled to worship or to support a church, and that establishing a church or requiring religious observances would be “an infringement” of “the natural rights of mankind.”

Finally, there were nine states with established (state sanctioned) churches in 1775. Between 1776 and 1778 five of those states disestablished their official religions, with the final state church (in Massachusetts) disestablished in 1833. So, not only did the founding fathers not intend for there to be a state religion, where a state religion existed as a carry over from the establishment of the colony that religion was disestablished and no religion was endorsed by the state.

I could go on but the clear point is that the founding fathers never intended for there to be a state sanctioned religion, and always intended for people to be free to worship as they saw fit with no interference from the government whatsoever. Anyone who claims otherwise is either ignorant of American history or willfully misrepresenting it. No one can legitimately claim to support the Constitution and an official religion because the prohibition against official religions is part of the Constitution. Of course, the Constitution is a living document and has been amended 17 times since the Bill of Rights. However, the idea of an official state religion not only runs counter to the foundations of the country but counter to the founding of the colonies. As much as one might cherish his or her religion, in the U.S. it is simply wrong to try to establish it over others.

LPDs, As Low As We Should Go

ASHRAE has released a series of changes to Standard 90.1 in preparation for the 2016 update.  Among those changes is the further tightening of LPDs (click here) in all space and building types.  In my opinion, these changes should be rejected by the lighting community.

Rather than provide tight, but reasonable, limitations on the power consumption of lighting systems, the LPDs proposed in the revision of Table 9.5.1 are so low that they clearly favor LED technology almost to the exclusion of all others.  They also strongly imply that energy efficiency is the most important criteria of a lighting system, regardless of the application.  Neither of these positions is appropriate for this document or the organizations that develop and maintain it.

The proposed LPDs are nearly impossible to meet by lighting designers who wish to exercise their best judgement, or meet client requirements, by selecting project appropriate sources of light other than LED.  In some cases this imposes an avoidable financial burden on the owner.  For example, LED luminaires with a combination of high output and smooth dimming to zero (such as those required for theatres, cinemas, houses of worship, etc.) are substantially more expensive than halogen alternatives, and may require more expensive control systems as well.  Clients requiring excellent color rendering (such as high end retail, art schools, museums, and health care facilities) are also compelled to purchase premium priced LED fixtures.

The only way that these low LPDs (and the even lower LPDs we assume will be proposed in the future) make sense is if they are paired with hours of usage to arrive at a time weighted limitations.  Even then, the LPDs should be high enough to permit designers and owners a choice in the technology that they use for a given application.  The proposed LPDs come very close to eliminating that choice.

I’m not saying that all buildings should be illuminated with incandescent light, or that LPDs should be abolished. I am saying, however, that the ever tightening of LPDs cannot go on forever, and that we have reached a tipping point where these limitations are having unjustifiable impacts on designs and budgets.  In my opinion, LPDs should not be further reduced for the foreseeable future.

Xicato Publishes IES TM-30-15 Results for its LED Modules

In a first (as far as I know) LED manufacturer Xicato has published TM-30 results for some of its modules alongside the CRI results for Ra and R9.  Menko de Roos, CEO of Xicato, says “At Xicato we are very supportive of TM-30-15 overall and recognize the need for an improved metric system along these two dimensions.”  You can read the full press release and find links to the results here.

I’m excited to see this greatly improved color rendering metric being used by a major manufacturer, and hope to see more manufacturers releasing TM-30 results soon.  If you still haven’t looked into TM-30 there is an increasing number of resources available to you.  TM-30 is available for purchase here. You can also view the recording of a webinar sponsored by the DOE and the IES and presented by two members of the IES Color Rendering Subcommittee, Michael Royer and Kevin Hauser.

Light and Health Webinar, September 30

Almost as if on cue, Philips Lighting is hosting a webinar on light and health presented by Mariana Figuerro, the Light and Health Program Director at Lighting Research Center.  I attended one of her in-person seminars earlier this year and I can say that she does a great job of explaining what aspects of light and health we can integrate into our practice now, and what aspects need additional research.  You can read more about the webinar here, or go straight to the registration page here.

Use of LED Lamps To Improve Health

Today’s New York Times has an article on several manufacturers’ new LED products that are intended to improve wakefulness, sleep, focus, and other aspects of daily life and health. The article appears on both the business and technology pages, but not on the health page, and I think that’s appropriate.  Although there are testimonials by the consumers of some of these products, there’s no discussion about any peer reviewed science behind them.  In fact, about two-thirds of the way through the article the author finally gets to the fact that, “Researchers are still determining how spectrum and intensity of light affect the brain.”  So, the article is an uncritical look at new LED products that make health claims.  We shouldn’t rely only on the claims of the manufacturers, though – remember the claims of 100,000 hour lifetimes for LED lamps?

I’m not saying that we know nothing about how light affects us, because we know quite a bit.  The question is, “Do we know enough to properly and safely integrate that information into our design practice?” and there things become uncertain.  So, before accepting the claims of manufacturers, or making the same claims to clients, it’s important for designers to be up to date on the current state of research and to understand the strength of the findings, as well as how (and if) those findings can be folded into a design.

There are a few web sites that I find useful for keeping up to date.  The first is the Health and Vision page of the Lighting Research Center’s web site, which has links to many of their recently published research papers.  The second is the Research page of USAI Lighting’s web site.  This page provides links to a mix of newspaper articles and scholarly publications on a variety of topics connected to LED lighting.  The third is the Research page of the IES web site.  Finally, members if the IES can  download copies of Leucos, and non-members can purchase copies.

LEDs continue to revolutionize the lighting industry.  Most manufacturers have ended  research and development for incandescent and fluorescent products. OLEDs are increasing in efficacy and prices are dropping, while new technologies (such as light emitting plasma and quantum dots) are on the horizon or already here. To preserve their client’s money, the occupant’s health and safety, and their own reputations, designers need to make sure that they don’t get swept up in the possibilities that are marketed to them before the facts are in.

TM-30 and Color Gamut

You may be familiar with the idea of a color gamut from displays or from RGB LED fixtures. In both cases the gamut describes the full range of colors that the device can create. In TM-30-15 IES Method for Evaluating Light Source Color Rendition gamut (Rg) has a somewhat different meaning. It refers to the average color shift of the 99 color evaluation samples (CES) under the test light source when compared to the reference light source. The reference source used in Rg is the same source used when calculating color fidelity (Rf) (as opposed to a fixed reference source as has been proposed in other gamut metrics).

A gamut index of 100 means that, on average, the test light source doesn’t change the hue or saturation of the CES compared to the reference source. An Rg above 100 indicates that the test light source, on average, increases the saturation of the CES producing colors that are more vivid. An Rg below 100 indicates that the test light source decreases the saturation of the CES producing colors that are less saturated.

The addition of a gamut index is a huge improvement over the single CRI (Ra) number that we’re used to. With Ra, every shift from a match to the reference source, whether it increases or decreases saturation, is treated equally and the direction of the shift is not reported. However, this is important information. For instance, research has shown that in many situations most people prefer a slight increase in color saturation. With Rg designers know the direction of the color shift, and the TM-30 calculation tool also shows the shift by hue and for each of the CES.

What’s the relationship between Rf and Rg? If Rf is 100 (a match to the reference source) Rg must also be 100. If the Rf calculation doesn’t indicate a mismatch with the reference source then there is no change in saturation. As the Rf value falls the potential range of Rg above and below 100 (indicating an increase or a decrease in saturation) grows. The calculation tool includes a chart that shows this relationship and gives a visual indication of where the light source in question fits.

Another graphic, the Color Distortion Icon, is plotted on the CAM02-UCS color space. In this graphic both the reference source and the test source are shown, along with an indication of the direction and magnitude of the hue shift caused by the test source.  Finally, we can even look at the color shift for each of the 99 CES.

A designer using TM-30 now has three big picture metrics to evaluate a light source: color fidelity (Rf), color gamut (Rg), and correleated color temperature (CCT). The designer can use TM-30’s calculation tool to examine the Rf and Rg of a light souce in as much detail as the project merits, from a very broad overview to a very detailed, color by color, evaluation.

The one thing that TM-30 does not do is provide guidance on the significance of the values it calculates. It is a Technical Memorandum that describes two calculation proceedures, not a design guide for using the results of those proceedures. Guidance will come later in the form of a TM-30 addenda or a design guide prepared by the IES, or guides prepared by other parties. In the meantime designers can begin to build their own understanding by comparing Rf and Rg values to the their visual evaluation of the light source, and by sharing the results of their work with others.

The pubication date has not been set, but now that the TM has been approved by the IES board of directors it should be available soon.  Keep an eye on the IES bookstore and on trade publications for updates. In my opinion TM-30 is a huge improvement over CRI, and I hope that the industry enthusiastically adopts it.

Note:  This post was originally published on June 15, 2015 but was taken down when the IES contacted me and claimed copyright to all graphics produced by the TM-30 calculation tool.  This seems to me as absurd as Adobe claiming copyright to all pictures edited in Photoshop, but I didn’t have the time to argue.  I took down the original post and have reposted it here, without graphics, and edited the text to omit references to graphics.