If you've been shopping for lights recently, you may have noticed something called "color temperature". You may have thought, "What is this? I just want to buy a light." The simple answer is, that number with a K behind it tells you what color light you're buying. If you'd like to know more click through to read the full story, but be warned. Things are going to get sciency.

Light temperature is measured in degrees Kelvin. You might have learned about the Kelvin Temperature Scale in your high school science class.  0 Degrees Kelvin is known as absolute zero. (Ringing any bells?) Well, what does temperature have to do with color?

via Derek Key

You've probably seen pictures of blacksmiths working before. When they heat up metal, it glows. As heat is applied to say a metal rod, it will begin to look red, then orange, then yellow and eventually white if it gets hot enough. A similar process happens inside of older tungsten light bulbs. As the filament is heated, it radiates visible light. As a filament gets hotter, the color of the light begins to shift. Color temperatures are based on the colors a filament radiates at different temperatures, more or less. (There's actually a more complicated explanation, and you can read about it here.)

We know what colors our eyes will see at the different temperatures. When we describe what color an LED light emits, we compare it (or correlate it) to these temperatures. That's why it's called "Correlated Color Temperature" or CCT.

What does Warm White, Neutral White, Cool White, etc. mean?

via Clarke & Sciami

When we describe what a specific color temperature looks like, we often use words like cool and warm. These descriptions have less to do with the actual color temperature than they do with how the colors look. Light that is more red, while technically a lower temperature, is considered "Warmer". While light that is more blue is considered "Cooler", even though it's technically a higher temperature.

What we call "Warm White" is very close to the color of traditional incandescent bulbs. It offers a warm glow that gives off a cozy vibe. This is recommended for more traditional interior designs.

What we call "Neutral White" is about half-way between Warm White and Cool White. It is still warm, but colors will look more vibrant. It is a nice compromise between the more modern Cool White and the traditional Warm White. Neutral White excels at displaying art.

"Cool White" is meant for more modern aesthetics and is especially great in offices. It is energetic and closely resembles daylight. Cool White is the best light for reading and detailed tasks.

Now that you know all about color temperatures, you're ready to choose the right lights for you!