How to Use “Class A Color” Designation for General Light Sources

Color qualities of electric light can be difficult to understand. What color do you really want for your lighting application? I, Dr. Bulb, have learned to follow “Class A color” designation as the most reliable indicator.

The lighting industry relies on correlated color temperature (CCT) and color rendering index (CRI) to communicate color qualities of electric light. However, neither metric can reliably predict human color perception. Therefore, the “Class A Color” designation is a better predictor of user acceptance of color qualities than CCT or CRI alone.

Provides Good Color Rendering

The color rendering properties of electric light cannot be captured by a single metric like CRI. Consensus among lighting specialists is evolving toward the belief that any useful system for characterizing the color rendering properties of light sources must be based on two metrics: fidelity and saturation. All dual‑metric approaches are, to date, better at predicting subjective judgments of good color rendering.

Provides Illumination with Minimal Tint

CCT has been used to communicate the apparent tint of “white” illumination sources. Research suggests most sources with chromaticities along the line of blackbody radiation do not appear white. In fact, people usually prefer sources of illumination along a “white” line more than those of the same CCT along the line of blackbody radiation. Experts hypothesize sources with chromaticities along that line should evoke minimum outputs from red‑green and blue‑yellow color‑opponent channels in the brain.

Appears Consistent with Other Color Sources

Color consistency is another important feature of manufactured light. No two products are ever exactly alike. Variations in raw materials and manufacturing processes among products lead to differences in color properties produced by different light sources. Chromaticity tolerance zones have been established for sources of a given CCT designation. These zones also would be used in the “Class A color” designation.


Consumers need some assurance that they will not be disappointed with the color qualities of lighting systems, nor with the product when installed and operated. By bundling color metrics together, the industry can save a lot of resources educating consumers about product benefits. The Class A color designation could not only be the seal of approval for color quality from manufactured sources, but also facilitate the transformation of the market to higher quality, more energy-efficient lighting technologies.


What Happens When Internet Connected Light Bulbs Get Hacked?

I, Dr. Bulb, have been fascinated with Wi-Fi-enabled LED bulbs, and have even tried them out for myself. But researchers at Context Information Security recently announced that they have been able to expose a security weakness in a Wi-Fi-enabled, energy-efficient LED light bulb that can be controlled from a smartphone. This got me thinking…

What happens when hackers take control? Could they turn people’s lives upside down? Or could they make life a little more amusing?

Simulate a Haunted House

Hackers could install a speech recognition program, allowing them to arrange to have the lights turn off every time their target spoke. Imagine this conversation:

Target: What’s for dinner? (lights go out)
Friend or Family Member: Turn the lights on so I can see what’s in the fridge.
Target: Okay, lights are on. (lights go out)

You get the picture. No one will believe that this is happening since the hacker controls when it happens.

Prevent Teen Pregnancy

Parents will love this one. When teenagers have their current crush over, the lights stay on as long as people are talking. Once the conversation stops, every light in the room starts blinking red. A program like this could be quite effective as birth control.

Get the Party Started

On the other hand, someone “in the mood for some lovin’” could program the lights to switch to an amorous dim red light when they want to get their partner in the mood. Of course, a down-side could be that passers-by will soon begin to notice the pale red light streaming out of the bedroom and start gossiping.

The future is here and it’s important to be cyber-secure. These wireless light bulbs can help to reduce energy costs and increase the longevity of the bulbs, but you have to make sure that your house is protected from invasion by password protecting your home Wi-Fi network or else things could start getting weird around your house.


Which State is the Greenest?

Check out this interesting infographic and see how your state ranks in sustainable energy. Maybe some more LED light bulbs could bring up some of those low rankings!

Produced by


Illuminate Africa!

Imagine a life where your day is done when the sun goes down. No evening basketball games. No late-night shopping trips. No vital tasks such as hospital visits. For the some 1.6 billion people worldwide with no access to electricity, this is their reality.

I, Dr. Bulb, was fascinated by Philips’ initiative to install 100 Philips Community Light Centers across rural Africa by 2015 as part of their “Philips Cape Town to Cairo Roadshow.” A light center is about 1,000 m² (3280 ft²), the size of a small soccer field, lit with new solar-powered LED lighting atop 8-meter-high poles fixed in concrete. In the past year, Philips installed about 40 light centers to extend the day in Egypt, Morocco, Ghana, Kenya and South Africa. Illuminate!

 The program is a vehicle for the company to raise awareness of how healthcare and lighting solutions can improve life in Africa. The installation of community light centers enables social and economic development life for rural communities. With a safe well-lit space, residents are able to host healthcare clinics, education and evening classes, sporting events, social events and commercial activities. I’d love to compete in a soccer game with this type of sports lighting!

 Because LED lighting is super energy efficient, the community light centers are able to run on solar energy with batteries that only need to be replaced every 4-5 years. No electricity is needed! Even better, locals can make money by renting out the space for commercial uses.

 I, Dr. Bulb, love how companies like Philips are using LED technology to improve quality of life! Hopefully LED applications like LED wallpacks or LED bollards  are the solution to continue illuminating rural areas across the world. Don’t forget to follow me on Twitter @doctorbulb and subscribe to my blog.


History of Lighting: Recreating the Moon?

On a hot summer day in 1882, Detroit’s residents gathered around city hall to witness drama, excitement, and most importantly—The Future. Unfortunately, LED lighting wouldn’t be invented for another century, but they had something equally as innovative and thrilling (for the time) to gawk at: moon lights.

 I, Dr. Bulb, was not around to witness the age of moon lights. And I’m not sure if I’d want to! In Detroit, the moon lights were five-hundred pounds of lights anchored atop a 150-foot-tall pole meant to simulate moonlight, according to The Atlantic. The actual purpose of the lights was overshadowed by the possibility of danger. Often the poor manufacturing of the support poles would cause the moonlights to come crashing down to earth.

 But it’s 2013 and I only see one moon in the sky. What happened to “The Future”?

 In The Age of Edison: Electric Light and the Invention of Modern America, Ernest Freeberg describes the age of moon lights. While an eventual failure, the moon lights represent the early days of electricity and lighting ingenuity. Americans wanted to illuminate their cities—but they weren’t sure how. Street lights would be far too complicated and expensive, so they looked to the sky and tried to recreate the moon. Charles Francis Brush, an inventor and entrepreneur, was contacted by the town of Aurora, Illinois to install six iron towers with arc lamps above the city. With Thomas Edison as one of his major competitors, Brush was determined to illuminate the country with moon lights.

 Sadly for Brush, many residents—and animals—were not happy with the new lighting systems. Light was everywhere at all times, killing exhausted animals who were unaccustomed to extended daytime. The moon lights could easily be blocked by trees or buildings, creating disorienting shadows. And imagine walking from day to night in just a few steps! Eventually they installed more towers to combat the issues, which defeated the entire purpose.

 Street lights are looking like a great idea at this point. If only they had invented LED lighting!

 The moon lights made it to Detroit in a business deal. Detroit wanted to be the “best lighted in the world” and Brush wanted publicity. Although many residents found the lights to be brilliant, others were not happy with the flawed method. The disadvantages soon overpowered the benefits and moon lights were replaced.

 Interested in seeing a moon light in person? In 1894, Austin, Texas purchased 31 of Detroit’s towers and 17 survive today.

 Now, we have more safer and more efficient mean of lighting such as LED wallpacks and LED bollards, the history of lighting has come a long way! Don’t forget to follow me on Twitter @doctorbulb and subscribe to my blog.


What’s A Watt Worth?

While attending my friend Henry’s house party recently, I was disappointed to find that not only did he not read my blog, but he also didn’t use LED lighting around the house! With an annual cost per watt calculation, I calculated that he was losing hundreds of dollars each year on the bollard lights lining the walkway to his house.

Using only 15w, today’s most efficient LED equipped reflector bollards have 80% luminaire efficiency and produce 800 lumens. The metal-halide lamps and ballasts around my friend’s house require 70w to produce 816 lumens—with only 24% efficiency! To put it simply, the bollards emit about the same amount of light, but the LED version uses 80% less energy.

If Henry keeps his bollards on for eight hours a day for seven days a week, it would cost $0.44 a watt each year. Twelve bollards equipped with 70w metal halide lamps and ballasts would be about $370 in energy costs. On the other hand, twelve 15w LED bollards would only cost $80. For every year Henry delays switching to LEDs, he loses $290!

But why do LEDs use so much less energy? Because of their small size, LED chips provide directional lighting, whereas metal-halide lamps emit light in many directions. The majority of the light in my friend’s metal-halide lamps was trapped inside the reflector-style bollards wasting most of the light. LED chips can direct all of their light at the reflector, which means they’re using most of the light originally produced. Less wasted light means less wasted money.

 After I gave Henry a hour long lecture on the savings of LEDs (it was a really fun party),the next time I visit him , I expect to find a walkway lined with LED bollards. Calculate how much money you’re losing each year by using an annual cost per watt chart and researching energy costs in your area. Do you think it’s time to switch to LED?

Don’t forget to follow me on Twitter @doctorbulb and subscribe to my blog.