LED color choice – Lighting by Jeffrey

Akira Kurosawa and Lighting

As a follow-up to seeing the English film, “Living” a friend allowed me to borrow his Janus Film copy of the original Akira Kurosawa masterpiece, “Ikiru.” I typically do not watch the “extra features” included in most digital packages, but the interview with the visionary director was too compelling to ignore. The talk was broken into various aspects of his approach to film. One was titled, “Lighting” so of course, I could not help but pay extra attention.

In his conversation on the importance of lighting, he mentioned that to embolden colors that appear on film, he would paint and tint reflector panels that would pick-up the set lighting and bounce additional color with light onto what was being filmed, thereby resulting in more dense, fuller tones. It is the reason why so many of his color films have such vibrant appearances. If you haven’t seen “Ran” give it a watch to understand the value this technique brought to the movie. Trust me, whatever you see on your flat-screen was better in the theater using projection. After so many years, I still remember it.

I started to think about its use in residential lighting. I knew a landscape lighting designer who used seven different gels or tinted blue filters on incandescent lamping to complement each varietal of evergreen, resulting in an otherworldly feel to the exterior spaces he lit. Perhaps the client didn’t know, but he and I suspect other designers certainly did.

Can we bring Mr. Kurosawa’s and my acquaintance’s dedication to color into the interior of a home? In fact, we may have already done that when we introduced LED to the home a few years back.

Incandescent light was VERY yellow, rendered dark blue, deep purples and browns poorly, but the amount of red did make it feel “comfortable/warm” to a large majority of the population. LED presents color in a different way because the spectral power distribution (a representation of the amount of each color in the visible electromagnetic spectrum) is different.

Don’t be frightened. The electromagnetic spectrum is easy to understand. Visible light spans from 380 nanometers to 700 nanometers. Ultraviolet light has a smaller measurement than 380nm (it appears to the left) and infrared light is larger than 700nm (it appears to the right.) The visible range begins after the ultraviolet light on the spectrum, runs from purple to blue, to green, into yellow, orange and finally red before disappearing from the human eye’s visible range into infrared light.

In this image, you can see the assortment of colors visibly represented across the horizontal, the intensity of each color is displayed vertically.

The incandescent light features a very small amount of intensity in the purple and dark blue area on the left, hence the reason it is so difficult to “see” the difference between a navy blue suit and a black suit.

All white LED starts with a blue diode that is influenced by phosphors. That blue seed is visible in the LED spectrum as the blue hump on the left, before the huge rise into light blue, green and yellow. The almost nonexistent “red” at the right is the reason humans feel that LED is somewhat cold, or less comforting than the “warm” old incandescent.

The good thing about LED is that the spectral curve CAN and HAS changed since the first LED were introduced into the market. The incandescent curve hasn’t changed since Thomas Edison. That means we have options today that were unimaginable yesterday. A 3000K output will increase the “hump” of blue slightly resulting in better rendering on purple, blues, blacks and even white. With the 2700K white light as illustrated here, the blue is marginally suppressed and the red is increased a bit allowing for better color rendering of warmer colors like beige, yellow, orange, wood and eathtones. Red is a VERY dominant color, so even with substantially lower intensity, it still renders the color well.

Most lamp and luminaire manufacturers now produce 2700K and 3000K LED products, so as consumers, we are faced with a very simple choice. Do we have a “warm” or a “cool” space? If warm, we should select 2700K products, cool means buying the 3000K option.

Akira Kurosawa’s movies are complex and will be studied by film scholars for decades to come. How he achieved some of the results will continue to illicit post-screening, coffee shop conversations for as long as we have movie fans. Choosing color in a residence is decidedly easier. As long as you grasp the underlying science.

Isamu Akasaki

Hiroshi Amano, Shuji Nakamura and Isamu Akasaki shared the 2014 Nobel Prize in Physics for their invention of blue, light emitting diodes (LED). Through the use of phosphors, the new blue LED was subsequently translated into the white light we understand and use in our daily life.

The creation may be of limited understanding to many, but the importance to lighting, design and the future of illumination is monumental. Quite simply, this creation “changed everything.” In the ten short years since their work became marketable, the way in which we illuminate our world has been upended and completely altered. This was a huge scientific accomplishment, but the impact on design has been seismic. Here are four ways in which this Nobel Prize for Physics has altered interior design expectations.

#1 – Color Choice

Prior to LED, light bulbs came in one color. That color worked nicely for warmer, earth toned palettes, but was found wanting with bolder tones. LED can be easily produced in a wide variety of colors from the warm, candle-like tones of 2400K to cool blue daylight at 6500K. This wide spectrum has resulted in rooms that better represent the aesthetic intent of the designer. Yellow, beige and wood are richer and more revelatory with warm LED color measuring 2700K. Blues, stainless steel, whites and black become more vibrant when illuminated by 3000K LED. Light is now an integral part of color selection and interior design.

#2 – Light Layering

If you think back to homes, built as early as the year, 2000, the concept of light layering was absent. Single luminaires, placed in the center of the room were de rigueur. Our subjective impressions of light bring us to react negatively to this type of illumination. Humans show a preference for peripheral light that varies in intensity. The same light also delivers a space that is perceived to be more relaxing and provides us with a feeling of privacy. Simply put, more and varied light starting at the perimeter and moving inward is preferred by most people.

Cove lighting, niche lighting and tray ceilings illumination was far more complicated and substantially more expensive before the development of LED. Now, designing an array of light that meets both aesthetic and preferred needs is easier. That is the result of this trio’s work.

#3 – Lighting That Supports Human Circadian Needs

The human body functions via the aid of our circadian system. That system is driven by the 24-hour, light-dark cycle of the sun. Since the Industrial Revolution and the introduction of second and third shift workers, humans have subtracted themselves from this cycle, thereby disrupting their circadian rhythm and in-turn the production of melatonin. When used carefully, LED can replicate blue, mid-daylight, white dawns and orange-red dusk. Light therapy, while still in its infancy is starting to help. We may still be a few years away from affordable circadian lighting that changes colors throughout the day in our homes and workplace, however without LED, this end goal would not be possible.

#4 – Light Preference

Prior to LED becoming the go-to source of energy efficient light, fluorescent light was the only option. While mature, good-looking fluorescents have been developed, they suffered from the bad reputation of the low-quality CFLs introduced in the late 1990s. With the bad taste those early CFLs left in the minds of designers and consumers, additional fluorescent use was going to be a hard sell.

Because of energy efficient advances in most every other electric product, lighting was consuming more and more of our electric use, peaking in 2008 at over 14% of typical residential electric consumption. The bipartisan, “Energy Independence and Security Act of 2007” mandated a change to more efficient lighting. Those efficiency demands made fluorescent the only option until LED lamps were introduced to the market in 2008. Their presentation of light was enthusiastically received. Consumers willingly switched to energy efficient LED. The preferred light is the result of the efforts of Nakamura, Amano and Akasaki.

For most people, the passing of a physicist barely merits a “click” on a news website. For interior designers, architects and lighting people a glass should be raised and an expression of debt shared. His work resulted in a paradigm shift in our understanding and application of lighting, all for the better.