What Does Kelvin Temperature Mean?
I’m sure many people at one time or another have wondered what those numbers mean in a light bulb part number. You will almost always see a number with a “K” after it on fluorescent, LED, and even some HID bulbs. This number tells you what the color temperature or Kelvin temperature of the light output is, or the light bulb color. For example, you often see a part number with “4000K”, “4100K”, or even “41K”. This tells you that the particular bulb’s color is around 4000 on the Kelvin scale. Traditionally, 4100K bulbs have been considered a “cool white” color, while 3000K bulbs are considered a “warm white” color. The lower the number on the scale, the “pinker” or “redder” the bulb is and the higher the number, the “whiter” or “bluer” the bulb is. A “daylight” bulb is usually anywhere from 5000K to 5800K, and anything above that such as a 6500K is considered “full-spectrum”.
When choosing the color of bulb you want, in a lot of ways it’s a preference, but there are some things to think about. The higher temperature bulbs have been shown to be better at displaying the true color of objects such as carpet, fabrics, or tile, where you really need to see what they look like. There is also evidence that the higher temperature bulbs are better for your eyesight when you’re working under them, especially the full-spectrum colors. The 3500K and 3000K are often used in dressing rooms because they make people look more “pink” and healthy and it helps sell the clothes. Many compact fluorescent bulbs are sold in a 2700K because the incandescent bulbs they were replacing had that warmer color and people were used to it.
Whiter Lights Are Not Necessarily Brighter
People tend to think the whiter colored bulbs are brighter than the pinker colored bulbs, but this is not the case. There is also another number which may be listed and it’s the “Lumens” or “Lumen output” number. This will tell you how much actual visible light comes out of the bulb, and sometimes the pink ones are just as bright.
These days, light bulbs come in a multitude of colors. Regardless of the names they give them such as “Soft Warm White” or “Natural White”, you want to pay attention to the number as well, when you are picking out your bulb color.