Good lighting design takes into account the needs and nature of human beings. Here, in no particular order, are five biological, psychological, and generally human principles of light.
Mood
A number of factors can affect mood including color temperature, lighting intensity and contrast. Color temperature: Measured in Kelvin, color temperature ranges from warm (2,700-3,000K) to cool (>5,000K). If you associate warmer color temperatures (yellow, orange, red) with a more romantic, laid back mood and cooler color temperatures (white, blue) with concentration and alertness—you’re not wrong. In fact, light color temperature can influence the way we feel about an environment, a situation or even a person. In general, a warmer color temperature evokes feelings of intimacy and being “at home,” while a cooler color temperature encourages an awake, alert state of mind.
© Justin Maconochie
Lighting intensity: The intensity of light can also affect mood—according to one study, the brighter the light, the more intense the emotion—essentially, if you’re already in a good mood, intense light will only make you feel even happier. On the other hand, if you’re depressed, a bright, sunny day could make you feel even worse. Lighting intensity affects not only mood, but the intensity of attraction (making that hot girl/guy appear even better looking) and the urgency of decision-making (Act now! This is a one time offer!).
Contrast: You can see the role of contrast in influencing mood most clearly in visual media: movies, television, and photography. Strong contrast can evoke feelings that right and wrong are relative and that robbing the nearest bank might be a good idea (film noir). Joking aside, most businesses strive to keep contrast to a minimum, favoring consistent, even lighting over dramatic flair.
Productivity
Many studies have explored the effect of lighting on productivity. In one study, visual acuity in elementary school students increased when the classroom switched to higher CCT (co-related color temperature) LED lighting. Essentially, students could read better when the lighting was closer in color temperature to daylight—which makes sense. One of the great things about LED lighting (other than the obvious cost-savings and energy efficiency) is that color rendering remains consistent even when lights are dimmed—making them ideal for classroom and office settings.
In addition, LED lighting systems can tune color temperature to mimic the effects of changing daylight or to boost productivity—for example, an office environment attempting to increase worker concentration and alertness in the afternoon can tune the lighting to a cooler color temperature, promoting efficiency and performance.
Sleep
Humans are designed to function on a roughly 24-hour cycle of wakefulness and sleep. Light is one way that our bodies set the clock. Human-centric lighting design takes into account natural rhythms of light and dark, incorporating changes in lighting intensity and color temperature over the course of a 24 hour cycle.
Exposure to blue light especially can inhibit the body’s production of melatonin—the hormone that signals to the body that it’s time for sleep.
Habit
Lighting can affect sleep and work habits in human beings. Here are some good habits to develop:
- Start your day with at least an hour of daylight. This sets your circadian clock and can improve mood, productivity and sleep.
- If you can, get outside during your lunch break.
- Invest in high CRI (Color Rendering Index) LED lighting in your home/workplace.
- Put down that iPhone at night. Limit exposure to blue light before bed—read a book under the soft, pleasant glow of a warm LED lamp. If the last book you read was in high school (or you’re reading on your phone or tablet), invest in an app that reduces the amount of blue light coming from the screen of your device.
Socialization
Geographers like to distinguish between the concepts of “Space” and “Place.” Space is defined as simply the physical location or environment—Maine, Abbey Road, Westeros, the taco stand down the street, etc.
© Justin Maconochie
Place, on the other hand, is subjective and emotional. My favorite definition of “Place” comes from April McCabe of the aptly named Place Partners: “Place [. . .] is multi-layered and subjective. It is created when the physical attributes, emotional connections, and psychological perceptions are combined to impart individual meaning and value.”
Space describes the visceral, gut-level response to a physical environment—it’s “Sawyer Rd.” versus “The street I grew up on, home, family, hot summer nights, two feet of snow, learning to ride a bike.”
Lighting can turn a “space” into a “place” by influencing social interaction among humans. Harsh, intense lighting can cast a glare of suspicion on others, while warm, low lighting can invite connection. Lighting design that doesn’t take into account the ways in which human beings interact with each other can not truly be called human-centric.
