What is Color Temperature?

I've never been so impressed with a blog article, that I've contacted the author, and asked for his authorization, so that I can post that article in my blog before.  I've found this posting so insightful and specific, that I've asked Matt Astrella from Alglo Engineering, if I could re-post his blog.  He said yes,  and I truly hope that you find it as helpful as I have.  

(Alglo Engineering has also come up with an unique tool that can help all interior designers, stay tuned to hear more about this new tool, below!)

What Is Color Temperature?

Color temperature is mostly a measurement of the amount of yellow or blue white a light is comprised of and is measured in degrees Kelvin (K). The term ‘temperature’ is used because designers often describe how warm or cool light appears, the more orange and yellow light is the warmer and the more white and blue, the cooler.

How Is Color Temperature Measured?

Color temperature is measured by a unit called the Kelvin (K). The Kelvin thermodynamic temperature scale is defined so that absolute zero is 0 kelvins (K). The measurement of color temperature follows similarly the color changes a piece of metal would experience as heat is applied to it. At first, the metal would glow a deep orange-red and then become more yellow-white and finally move to the blue spectrum. The lower numbers on the light temperature scale (2700K is usually the base) contain a more yellow-orange color, the middle of the scale are white and the top of the scale (often ends at 6500K) you get very bright white to blue color.

How Do I Choose Which Temperature to Use?

The color temperature you want to use to illuminate your room depends mostly on the mood you are looking to create. If you are using warm furniture colors such as rich dark woods, reds in oriental rugs, and wall paint, 2700K to 3000K bulbs will bring out those colors more. For rooms with light woods, whites, grays, and blues, and lighter wall colors such as lighter shades of purple and blue the 3500K and even up to 5000K bulbs will compliment best.

Interior designers can swap out light bulbs or use an LED Design Kit to show how different materials will look under the different temperatures.

Another tip is to base it on what the dwellers are using the room for. For example, many people will find a formal dining room more appealing with warmer light, while for a large, open-plan office neutral to cool white light is the better choice. Offices often use 5000K fluorescent lighting that creates a cool white light that has been said to keep people alert and awake.

It can also be aligned with how much natural light the room gets and whether you want to keep that same feeling through dusk and into the night or if you want to switch it up come dark. A room in full sunlight during the middle of the day will be a bright, blue white (around 5500K) while horizontal daylight is near 5000K, daylight on an overcast day is more blue (6500K), and during sunrise and sunset you get extremely warm light close to 1800K.

What Products Fall Into The Different Temperature Ranges?

You can purchase LED products in any temperature between 2700K and 6500K. Solid State Lighting makes it easy to adjust color with dyes.

Metal Hallide and Fluorescent products can also be found in different ranges across the spectrum.

• < 2700K – Warmest: These light temperatures are produced by fire and the sun!
  
  
• 2700K – Warm Light: Most incandescent light bulbs produce warm light which is why they are often used in restaurants and dining rooms to create a warm, comfortable environment. Halogen lighting is also in this range.
  
  
• 3000 - 4000K – Soft, Neutral Bright Light: Light within this range still has a little warmth to it but is fairly neutral. A lot of LED products and some soft/warm CFL bulbs fall in this range for use around homes to create a large amount of useful light.
  
  
• 5000-6500K – Bright White/Daylight: Fluorescent lighting and most CFLs fall within this range and is used in applications where natural light is desired.

Matt Astrella

Editor's note:  Please click on this link, to see the Interior Designer's Light kit, that helps show how different lighting can widely change the colours of the item.  I can imagine this tool being helpful when out at various showrooms, you could bring the light tool with you, take the item aside, then shine the light on the item, to show how it looks with the client's own lighting.  Saving many costly mistakes.