Fiddling with what you see

One of my back-burner trade journals is Architectural Lighting, a generally product-oriented magazine focused on…lighting. The July/August 2015 issue has an article on LED lighting that caught my eye, and is making me question reality.
As we all know, the sun is the original light bulb. It is not too hard to recognize that the sun’s light is the standard against which we judge all artificial light. We also know that the sun’s light is different at dawn and dusk; it is the sun’s light at zenith that defines white light. The zenith sun gives us true colors.
Artificial light has generally done a poorer job at rendering colors than sunlight. In 1964, the CIE (Commision Internationale de l’Eclairage) developed a method to test artificial light’s ability to render colors using eight color chips. These chips are from the Munsell color set, the traditional standard system of hue, value and chroma. It is interesting to note that Munsell developed his color set by using humans as the perceivers of color. There was no effort, nor was there the means, to use a digital, objective method of color recognition.
The CIE’s color fidelity metric is called the Color Rendering Index, or CRI. CRI values greater than 80 indicate the artificial light source is doing a good job in illuminating colors for human consumption. Lamps, or light bulbs as they are commonly called, are sold with their CRI on the package. A CRI between 80 and 100 indicates that a lamp will illuminate those eight Munsell chips so they look about the same as they would under direct daylight.
Early on, LEDs did a poor job with color rendering, so they had low CRI values. Because of technology improvements, and because of the digital nature of LEDs, which are also called solid state lighting, LEDs can now have very good CRIs. They can also be tuned to highlight certain colors at the expense of others. This ability to manipulate the color rendering ability of LEDs leads us to a very interesting place. Because so much of what urban people do is inside, and therefore illuminated by artificial lighting, it is possible to alter the way objects appear by altering the lamps used to illuminate those objects. The AL article gives the example of the Staples Center in Los Angeles: the LED lights are tuned to make the LA Lakers’ yellow and blue jerseys pop.
On a more mundane note, printer paper is often coated with a material called fluorescent whitening agents (FWAs). These “optical optimizers” are substances that absorb ultraviolet light (invisible) and emit it back as blue light (visible). This gives printer paper an artificially enhanced whiteness. Certain LEDs can add to the enhancement effect of FWAs, thus making the printer paper appear even whiter than it “really” is.
Thus, a clever manufacturer and retailer could work together to create products that when viewed under certain favorable lighting conditions, are even more whatever than they would be under zenith sunlight. This is where the Architectural Lighting article begins to stray into the Frankenstein realm. Closing with the heading “Color and the Real World”, the article candidly states that the way humans perceive everyday things, such as bread, can be manipulated by the conscious tuning of artificial lighting. We all knew this was possible. It is the digital nature of solid state LED lighting that will allow lighting manufacturers the ability to do the tuning as a matter of course.

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Principal at Sealander Architects, Ellsworth Maine. Revit guru. Married with 3 children. Avid gardener. Lived in San Francisco for nine years. Master in Architecture from Columbia University Bachelor of arts in religious studies, Wesleyan University. Graduated Staples High School, Westport CT. Hope to spend some time in Hokkaido before all is said and done.
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