Light is light, right? Not exactly. The light emitted from the overhead fluorescent lights in your office is nothing like the light emitted from your favorite chandelier at home or from the bedside lamp that reads your favorite novel to help you fall asleep.
This is because different light sources produce light with different color temperatures. In the early days of energy conservation, everyone recommended replacing incandescent lamps with fluorescent lamps because they used less electricity. Few people liked the trade-off because of the quality of the light the energy-efficient bulbs produced.
How color temperature works
To understand why color temperature is important, you must first understand what it is. This can be a tricky concept, so let’s break it down to the basics.
Imagine a hypothetical black metal object, such as the filament of a light bulb. Now start heating this filament with hypothetical fire. As the filament heats up, it starts to glow, first red, then yellow, then white and then different shades of blue as the flame gets hotter and hotter.
Certain temperatures of this flame, measured on the Kelvin temperature scale, correspond to different wavelengths of the filament’s light. The bottom (around 1800 Kelvin or 1800K) corresponds to the intense red-orange light of a match or candle. At the top (15000K and above), the measurements correspond to the perceived light looking up into a clear, blue sky.
You are probably familiar with terms such as “cool white” and “warm white” lighting, such as those seen with a standard incandescent or fluorescent light. If you read the fine print on the back of a light bulb package, you may even find an approximate color temperature in degrees Kelvin.
Most commercial lighting falls between about 2000K and 6000K, but two color temperature levels dominate. About 2700K is generally referred to as ‘warm white’ or ‘soft white’. These lamps are designed to approximate the typical incandescent bulb and give an orange colored, cozy, “warm” light just like grandma’s house. Warm light is considered a comfortable home light best suited for use in the home.
At about 3500K we enter the realm of ‘cool white’ or ‘bright white’. Lamps with this color temperature take on a more neutral color and may appear to have a slight blue cast. Standard fluorescent lighting is typically produced at this color temperature, which is what you will find in most business environments, as light at this wavelength is considered ideal for reading and other detail-oriented tasks.
Note that these are all estimates and averages. Different spheres produced with different materials and techniques will vary greatly in their color temperature. Professional lighting such as that used by photographers and filmmakers can vary well beyond this narrow range and can even combine different colors of light in one device.
Using the terms “warm” and “cool” is a bit paradoxical, because if you look at the Kelvin scale, you can see that the “cool” light is actually hotter than “warm” light. The terms warm and cool are not intended to describe the actual temperature of the flame used to produce the light, but rather the aesthetics these lamps generate.
In addition, color temperature ratings on their own are not always entirely meaningful. The color temperature of the sun is measured at about 5600K, but the actual sun itself varies greatly in temperature (reaching millions of degrees internally). Only the visible part of the energy radiated by the sun that we detect as light approaches the color temperature.
Adjust the color temperature to your environment
If you’ve ever replaced a light bulb with a fluorescent light and noticed how cold, unpleasant, or downright ugly the room looked after your upgrade, you’ve experienced how dramatic the color temperature can be.
Everything in a room is affected by the light source in that room. A wall that is white under a 3200K light source can look green under a 4000K light source. That same wall under a 2500K light source can look yellow. That is why designers advise you to place lighting elements and choose lamps before painting and decorating a room. “The color paint you choose under the fluorescent lights at a hardware store may look very different if you buy it under the light bulbs you have at home,” said Cory Bergeron, an author and video production professional.
Aside from the look of your room, the color temperature of your light can have some subtle and not so subtle effects on the way you live and work.
Danyelle Kukuk, director of product and category management for Batteries Plus Lamps, says lamps that mimic daylight (in the 5000K to 6500K range) are becoming increasingly popular in a variety of rooms. She notes, “Some customers appreciate having daylight lamps in their bedrooms because the color of the light, which mimics daylight, helps them get moving much faster in the morning than the warm, cozy soft white lamps.
In addition, many of the reading lights on the market have daylight temperature, as the color provides a great contrast between black letters on white or off-white paper, making it easier on the eyes to read. Kukuk also says daylight lamps are popular in bathrooms because they make it easier for women to see how their makeup looks outdoors.
Some research suggests that light in the blue parts of the spectrum can help you wake up in the morning, making cool white and daylight lamps especially suitable for bedrooms. “This ‘high Kelvin’ light can activate a photoreceptor called melanopsin that helps set your body’s daily cycles and keeps you more attentive and alert, so you can read and study longer, understand and understand better, for example. make fewer mistakes. ”said Michael Gottsacker, former marketing director of Verilux, which sells light therapy products.
That said, there’s really no need to replace your warm bulbs with daylight bulbs (which will kill the romantic mood in the evening and make it hard for you to fall asleep). One option would be to install color-tunable smart bulbs that are supported by apps that automatically adjust brightness and color temperature according to the position of the sun.
For example, Cree Lighting recently shipped a series of Wi-Fi connected smart bulbs with an app that has a ‘follow-the-sun’ setting. This automatically changes the brightness and color temperature of the light they produce to gently wake you up in the morning, keep you energized during the day, relax in the evening and fall asleep at night. You can see a screenshot of the app below.
Whatever you do to change the light around you, remember that it affects your mood and your overall health. “Light can actually make your immune system work more effectively,” says Sally Augustin, Ph.D., a practicing environmental psychologist.
How to tune the color temperature in your home
There are a few popular basic strategies when it comes to choosing lamps for your home. Perhaps the most popular is to choose a color temperature that you like – usually in the warm light range – and install these bulbs everywhere. This has the advantage of uniform lighting in your home, making transitions from one room to another less jarring.
Alternatively, warm lamps can be used for primary lighting in areas such as the living room, dining room, bedrooms and hallways; and cool or daylight lamps can be used where more attention to fine detail is required. Bathrooms, the garage, offices, the kitchen (especially fixtures directly above work areas) and focused work lights such as reading lights are good candidates for cool white or daylight lighting. There are no hard and fast rules as to where which type of lamp should be used. Ultimately, you will have to experiment to see which one suits you best in each fixture in the house.
But that’s just the beginning. With the advent of LEDs, which are available in a much wider range of colors than was available through other technologies, “color matching” has become an increasingly popular option for consumers who want to truly define their home through lighting design.
With a new type of LED lamps you can switch between cool and warm light – or put the lamp in a different color under the sun. Products in this fast-growing space include Philips Hue, LIFX, Sylvania, Cree Lighting, GE Lighting, and Nanoleaf. Each bulb is designed to replace your existing bulbs and many can be controlled with a mobile app over a wireless network (not necessarily Wi-Fi). With some, you can use the app to adjust the color temperature (or pick a wild alternative color to create a fun or festive mood), in addition to turning the bulb on and off and setting up schedules for the same.
The big advantage of adjustable lamps is that you do not have to choose a single lamp for every room in the house. According to Catherine Feliz, lighting product manager at Philips, the Hue system has four preset color temperature “recipes” built into the app: relax, read, concentrate and recharge your batteries. So, she says, if the kids ages five to six are always doing homework in the family room, you can program Hue to ‘focus’ during that time, about 4300K, and later switch to ‘relax’, about 2100K. , to help your body relax at the end of the day. “
This story, “How to Optimize Your Home Lighting Design Based on Color Temperature,” was originally published by