The “colour temperature” of any white light indicates the shade of white.

“Warm white” generally means a yellow-ish type of white, and “cool white” means a blue-ish kind of white. Somewhere in between lies “daylight white”, which is pretty much the whitest kind of white. Cool, warm and daylight are pretty imprecise terms though. A more accurate system indicating the tint of the light is called the colour temperature, or Correlated Colour Temperature (CCT).

A standard incandescent lightbulb is rather yellowish at about 2,700K and a normal halogen is slightly “cooler/whiter” in color, about 3,000K.

For interior lighting in homes, especially in the Western world we have grown accustomed to incandescent and halogen lighting, so we have a comfort with the “warm” colours they produce.

In more industrial settings, and for higher intensity lighting ie. “high bay” lighting, higher color temperatures of 4,500 to 5,000K are accepted. Metal Halide lights (HID) have traditionally been employed for this application, but of course LEDs are now available to do this job more efficiently.

Some specialty applications such as jewelery case lighting often use “cool” bluish lights of 6,500K or higher, in order to accentuate the sparkle and clarity of diamonds, silver and jewels.

Integrated Track Heads are mainly 3000K (as it’s the most popular CCT).

2700K is similar to the color of a regular incandescent or halogen light, which looks a little yellow or “warm”. 3000K is a little bit more white, but is still in the “warm” range. 4000K is approaching sunlight colour temperatures, but still a bit on the warm side. …Continue reading