Correlated Color Temperature and Color Rendering Index

Correlated Color Temperature (CCT)

CCT is what is used to describe the color appearance of a white light source. It tell consumers if the light source comes off more yellowy gold or more blue.  Light sources are described as warm (yellow) and cool (blue) in design, but they are assigned an actual number in Kelvin to describe the color for consumers. The Kelvin number refers to the appearance of the theoretical black body heated to high temperatures. As the black body gets hotter it will go from red to orange, then yellow, white and lastly blue.

Color Rendering Index (CRI)

The CRI is what indicates how well a light source renders colors. It is based on a scale from 0 to 100, when compared to a reference light source of a similar color temperature. The test involves measuring the extent to which a series of eight standardized color samples differ when illuminated under a given light source. The average shift in the eight color samples is then reported as Ra or CRI. This measurement is useful to know how other colored objects in the room will appear under the light, and is useful with paint colors and paintings.

More Lighting Terms!

Ibulbsn continuing with our theme from our last blog post, we’ve found some more lighting terms that are widely used and rarely fully understood by our lighting consumers.




Total Radiant Energy

Previously, we spoke about the three different wavelengths of light, visible light, infrared and ultraviolet. Total Radiant Energy is the measurement that is used to describe the total of these three wavelengths.

Lumens per Watt

Lumens are a measurement tool to determine the amount of light that is produced in the visible spectrum. Lumens per Watt is the number of lumens divided by the total watts used to create the light. It can be helpful to use this number to know how bright the light will be.

Rated Lamp Life

Rated lamp life is a measurement tool used to determine how long the light source will last. The longevity of a light source is established through laboratory testing.  The scientists determine the “rated lamp life” by collecting a sample group of lamps and testing the source, subjecting it to several starts per day.  The length of time required for half of the lamps to burn out determines the rated lamp life.

This process is done differently for LED light sources. LEDs do not burn like the rest, and over time their brightness can diminish. The rated lamp life (example 50,000 hours) for an LED isn’t for when it burns out, it’s for when the LED will likely be shining at only 70 percent of it’s original brightness.


Many energy efficient light bulbs are made with the ingredient Mercury. Fluorescent lamps and high intensity discharge lamps are the most common types of bulbs with mercury in them. The ingredient can be harmful and toxic to humans in large amounts so caution when handling these products is always advised.

Lighting Terms and Definitions – Wavelengths

When shopping around for your lighting options you’ll be bombarded by lighting terms on packaging and sales people. Understanding what these terms mean can make the difference between buying the right product and buying something that looks completely different than what you were going for. Over the next few blog posts we’ll be explaining some common terms.

Visible Light

Visible light is the actual light that the human eye can detect. We can detect electromagnetic radiation wavelengths that are long and short.  Typically the human eye can detect wavelengths between 400 nanometers (nm) and 750nm. The shorter the wave the more blue the light will appear and the longer the wave it will appear red in color.

Infrared (IR)

Infrared (IR) wavelengths can be anywhere from 1mm to 750nm. It can be detected as heat from a light bulb or even a fire. IR wavelengths of electromagnetic radiation are longer that what the human eye can see.

Ultraviolet (UV)

The length of UV wavelengths can rance from 100nm to 400nm. The human eye cannot see this type of light. Ultraviolet waves come from sunlight, fluorescent light, and some degree incandescent light. UV light can, over time, degrade the components of paper, photos, ink, paint and some adhesives.

Stay tuned for more lighting terms defined in our next blog posts!

Harold’s Lighting – Seafair Parade and Festival

Harold’s Lighting is proud to help sponsor the 65th Annual ‘WALLINGFORD FAMILY’ Parade & Festival!

A Seafair Sanctioned Community Event, Co-Produced by the Wallingford Community Senior Center and the Wallingford Chamber of Commerce.

For 65 years Wallingford has played host to the longest running Seafair Parade, known as the Kiddie Parade.  Families come from far and near to watch, participate in and enjoy this traditional event.  This year, our parade will be held on Saturday July 5th beginning at 11AM.

Parade – Starts at 11am.

The parade features kids as major participants and includes families and local businesses. Drill teams, local marching bands and family oriented organizations will be represented in the Parade.

This year’s theme is “Green Summer Up!” Costumes and participants that demonstrate environmental awareness, recycling/composting, gardening and other “green” subjects are encouraged!

Hope to see you there!