“What is color? No object of itself alone has color.
We know that even the most brightly colored object, if taken into total darkness, loses its color. Therefore, if an object is dependent upon light for color, color must be a property of light.
And so it is.”
Paul Outerbridge, Photographer 1896 – 1958
Have you ever wondered why things look different when you change a light bulb, say swapping a compact fluorescent for a good old incandescent? It is because the compact fluorescent has different color properties than the incandescent. The primary difference is know as color temperature.
For most common purposes color temperature is generally referred to as warm or cool, warm meaning more of the red spectrum in the light source and cool meaning more of the blue. Some scientists theorize that humans are pre-programmed to be more accepting of warmer color temperatures because our ancestors, for all the millennium, only experienced light from campfires and torches which is very warm light. This may or may not be true, but it is interesting to consider.
Of course preference for warm or cool light is a personal matter and varies among cultures around the world and even between areas in the United States. Residents of Northern climates tend to prefer warm light and residents of hotter ares lean toward cool. Here is another interesting fact: Sunlight changes its color as it crosses the sky. At dawn and sunset the sun appears more reddish, due to the filtering nature of the denser atmospheric layer it’s rays are passing thru at that angle. It has a correlated color temperature of approximately 2000°K at sunrise / sunset, and 5600°K when directly overhead.
Why is all the important to you? It is important because, for example, if you buy draperies for your house at a window treatment store they might not look the same in your house as they did in the store. Or, if you buy your draperies in your home at noon, they will not look the same at sunset. Just be aware the color is in the light, not in the surface from which that light is reflected.
For good, concise information and interactive examples of color and other light facts, consider downloading the Underwriter’s Laboratory app, LightSmart. Another good resource for lighting information is the American Lighting Association‘s web site. And, of course, please visit fogglighting.com to read our blog posts and learn how we might help you solve any lighting problem or challenge you may have.
Please be sure to think about floor lamps as you consider how to add light to your rooms. Floor lamps add interesting design elements and provide a pleasing layer of light.
In living rooms and family rooms you do not need a specific amount of illumination to perform tasks, you need layers of light to add interest and make the room feel inviting for friends and family.There are thousands of different styles of floor lamps from which to chose, something for every taste and situation.
Please visit FoggLighting.con for more useful suggestions. We are here to help if you need it.
Technical Explanation: The CRI is a unit that measures the ability of a light source to reproduce the colors of objects faithfully in comparison with an ideal source of light, or natural sources such as sunlight. The CRI is a determined value from 0 to 100, with 100 being the value “perfect” or daylight.
Real World Explanation: The CRI determines how you and your surroundings appear to you and the other people in your environment.
Looking at this photo, would you rather look like 50 or 100? Of course 100 is much more preferable. In our world of lights and lighting, the closest thing to the perfect value has traditionally been the good old incandescent light bulb. Now that regular incandescent light bulbs are impossible to find in most retail stores we are forced to find reasonable alternatives for our homes and offices. The alternatives to incandescent light bulbs have been compact fluorescent, CFL’s. CFL’s are now quickly being replaced with LED’s. All of these new light bulbs are not equal however. Some have high CRI values while others do not.
For example: I went to a new location of a coffee shop that I go to every now and then. The new location is being lit with LED track heads without much natural daylight. The old location is lit with regular fluorescent commercial style fixtures with lots of natural daylight. There is an employee who transferred from the old location to the new and it is astounding how differently that person looks under the LED illumination. The only reasonable explanation is that the CRI of the LED’s is really low. Skin tones, eyes, clothing…everything looks washed out.
Do not let that happen to you. You want to look good all the time. If you use low CRI light bulbs in your bathroom or dressing room, your make-up and clothing will look different outside in the daylight that it did when you got dressed and applied your make-up in your house. That is because of the poor color rendering of those light bulbs. All light bulbs now have labels that tell you the CRI. Best of all, good ones are not much more expensive than bad ones and using the good ones will enhance your appearance.
The Underwriter’s Laboratory app, LightSmart, has some really good information and examples of CRI and other useful lighting information. The American Lighting Association is another good resource to check out for lighting information. Please visit fogglighting.com for more useful information and please like us on Facebook.
Here is an example of what is happening in the the world of lighting today and what will continue to happen in the foreseeable future. LED’s are all the rage and designers are finding all sorts of new ways to incorporate them into light fixtures. The reasons are clear: LED’s consume far less energy than incandescent light bulbs, LED’s are cool to the touch, LED’s have better color temperature than they did in the past, LED’s have a super long life, and LED’s are small so fixture design can be very creative. In addition to LED fixtures like this one, LED light bulb design is evolving very quickly also. Technicians are finding ways to make them more attractive and more like the good old fashioned incandescent light bulbs. Some of the new LED light bulbs even grow warmer in color temperature as they are dimmed, just like incandescent light bulbs do. Additionally, new, more efficient heat sink materials are being developed which allow LED light bulbs be more streamlined and closer in appearance to both A-lamps and candelabra bulbs. Pretty soon you will be able to use LED bulbs in chandeliers and not notice a difference between them and the candelabra bulbs they replace. Best of all, LED’s are becoming less expensive all the time as manufacturing becomes more efficient and more manufacturers enter the marketplace. As with anything though, I urge you to be careful when buying any LED product as there still are huge quality differences among the myriad of products and producers out there. Try to see the product before you buy it to make sure the color of the light is acceptable to you. I recommend buying dimmable LED light bulbs and fixtures – some LED’s are not dimmable. I also recommend caution in using dedicated LED recessed lighting fixtures. Once you install them they are in the ceiling a long time and the quality of the light might not be satisfactory for you. Instead, consider buying a regular recessed fixture and using an LED light bulb. That way you are not locked in. Please visit our website www.fogglighting.com and like us on Facebook. You also might be interested in the Underwriter’s Laboratory app, LightSmart, which can be downloaded from the App Store. It has all kinds of great information about lighting…and its free.
Re-Printed From Residential Lighting Magazine November 2013 Issue
A Lighting Research Center study on lighting systems for Alzheimer’s patients could help an aging population.
Residential Lighting: Tell us how light levels affect circadian rhythms.
Mariana G. Figueiro, Ph.D.: Circadian rhythms are the rhythms in our body that repeat approximately every 24 hours. Light/dark patterns’ incident on the retina entrain our circadian rhythms to the 24-hour solar day. In the absence of this entraining stimuli, our circadian rhythms run with a period slightly greater than 24 hours. Light needed to activate the circadian rhythms is higher and “bluer” than that needed to activate the visual system. The circadian system is also looking for contrast between light and dark, so constant light or darkness is also not recommended. This might be what is happening with Alzheimer’s disease and related dementias (ADRD) patients, who tend to be in dim-light environments and constant-light environments. Increasing circadian light during the day and reducing it at night might be important for better sleep. We studied an elderly population with sleep disturbances and one with ADRD. In both cases, light helped them entrain to the solar day and be more awake during the day and sleep better at night. While the study is ongoing, preliminary results show that exposure to daytime light that is brighter than the ones found in assisted-living facilities and nursing homes and look more “bluish-white” than an incandescent light source, with less light exposure during the evening hours, can help ADRD patients sleep better at night and reduce agitation during the daytime hours.
RL: What kind of light is needed?
MF: Daylight is an ideal light source for the circadian system. A light source with a correlated color temperature of 6500K or higher would be ideal for daytime, along with light levels at the eye of at least 600 lux. In the evening, the use of warmer light sources, such as a 2700K with no more than 50 to 80 lux at the eye, is recommended. We also suggest a night lighting system that provides a low level of warm color, with horizontal/vertical cues to help with postural control to minimize falls. Lighting controls will play an important role because the daytime lighting system is different than the nighttime lighting system. In addition, personal sensors will become a key tool to allow for lighting schemes that promote entrainment at an individual level. Each person is different and responds to light differently. We need to be able to measure our circadian light/dark exposure and from that information design a lighting system that responds to our needs.
RL: Do LEDs and CFLs run counter to what Alzheimer’s patients need?
MF: Quite the contrary. These two light sources offer the possibility of using high correlated color temperature unlike incandescent lamps. Also, daylight can be energy-efficient and is a great light source for this application. In our study, we used GE Aquarium lamps that have a CCT of about 9200K.
RL: Is there more work to do?
MF: Yes. We have to start thinking about residential lighting that is coordinated with our work and school environments. In order to know when to add and remove circadian light to promote entrainment, we need to monitor our 24-hour light/dark exposures. In the case of older adults living in controlled environments, that task is easier. But for those of us who move from one building to another during the day, we need to monitor our light exposures and then have a system that can communicate with the sensors and feed information about the kind of lighting needed in the home. So the home environment will be a dynamic, individualized system that will respond to a person’s overall light exposures.