For a lot of our spots, we indicate the temperature of the white light. However, that has nothing to do with the warmth of a spot, but with the „color“ of the white light. So why are we talking about temperatures?
To explain that, we have to go back in time. The famous men, who essentially contributed to classifying colors by temperature, were Lord Kelvin and Max Planck. In the 19th century, the latter found out that a black metal body glows in different colors when heated by electromagnetic radiation. The higher the temperature of the metal, the shorter the wave lengths of the light emitted by the black body. That means: The body starts glowing in a in a dark red color at low temperatures and becomes brighter and brighter. In those days, temperatures were measured in the unit „Kelvin“, named after the Lord. This way, the classification of colors in degrees Kelvin developed. Concerning color temperatures, the prefix “degrees” is not used nowadays
This is why we still speak of color temperatures today. Take this as a rule of thumb: The higher the color temperature is, the cooler the light appears. A warm white is at 3300 K, a cold white at approx. 5600 K. Sun light, by the way, is a „cold“ white at almost 6000 K.
So if you see a spot with the description „warm white“ or „cold white“ in future, you know exactly what it means. By the way: Warm white colors create a rather harmonious mood, cold ones create a more realistic daylight atmosphere.
