Color temperature: The color of the absolute blackbody changes with temperature. If the color of the light source's emission is exactly the same as that of the absolute blackbody at a certain temperature, the temperature is called the color temperature of the light source, expressed in Tc, in K. The common color temperatures of light sources include 2700K, 3000K, 4000K, 5000K, 5700K, 6500K, etc.

Color coordinates: The coordinates of a color, usually represented by x and y, can accurately represent the color. As shown in the CIE1931 horseshoe diagram on the right, different positions have different color coordinates (x, y).