How the color of a heated metal changes:

------------------------------->>> Increasing temperature

Lamps can be described as "Warm" or "Cool" based on whether they are yellowish white or bluish white. Color Temperature (measured in Kelvins) is a scientific scale to describe how warm or how cool the light source is.

As a piece of metal is heated, it will go through the color changes shown on the left. We can use this scale to describe the "Color Temperature" of a light source.

When we say a lamp has a Color Temperature of 3000 Kelvin, it means a glowing metal at 3000 Kelvin would produce light of about the same color as the lamp. Instead, if the metal is heated to 4100 Kelvin, it will produce a much whiter light..